[1/3] pstore: add multi-backend support

Message ID 20240205122852.7069-2-xiangzao@linux.alibaba.com
State New
Headers
Series pstore: add multi-backend support |

Commit Message

Yuanhe Shu Feb. 5, 2024, 12:28 p.m. UTC
  Currently, pstore supports only one backend open at a time.
Specifically, due to the global variable "psinfo", pstore only accepts
the first registered backend. If a new backend wants to register later,
pstore will simply reject it and return an error. This design forced us
to close existing backend in order to use the new ones.

To enable pstore to support multiple backends, "psinfo" is replaced by
"psinfo_list", a list that holds multiple "psinfo". If multiple backends
are registered with the same frontend, the frontend is reused.

User can specify multiple backends that are allowed to be registered by
module parameter "pstore.backend=" separated by commas or "all" to
enable all available backends. If no pstore.backend was specified,
pstore would accept the first registered backend which is the same as
before.

Signed-off-by: Xingrui Yi <yixingrui@linux.alibaba.com>
Signed-off-by: Yuanhe Shu <xiangzao@linux.alibaba.com>
---
 fs/pstore/ftrace.c     |  29 +++++-
 fs/pstore/inode.c      |  19 ++--
 fs/pstore/internal.h   |   4 +-
 fs/pstore/platform.c   | 225 ++++++++++++++++++++++++++++-------------
 fs/pstore/pmsg.c       |  24 ++++-
 include/linux/pstore.h |  29 ++++++
 6 files changed, 248 insertions(+), 82 deletions(-)
  

Comments

kernel test robot Feb. 6, 2024, 8:05 a.m. UTC | #1
Hi Yuanhe,

kernel test robot noticed the following build errors:

[auto build test ERROR on kees/for-next/pstore]
[also build test ERROR on kees/for-next/kspp shuah-kselftest/next shuah-kselftest/fixes linus/master v6.8-rc3 next-20240205]
[cannot apply to aegl/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Yuanhe-Shu/pstore-add-multi-backend-support/20240205-203438
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
patch link:    https://lore.kernel.org/r/20240205122852.7069-2-xiangzao%40linux.alibaba.com
patch subject: [PATCH 1/3] pstore: add multi-backend support
config: csky-randconfig-r071-20240206 (https://download.01.org/0day-ci/archive/20240206/202402061551.EkLBF7yD-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240206/202402061551.EkLBF7yD-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402061551.EkLBF7yD-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

>> fs/pstore/ftrace.c:30:47: warning: 'struct ftrace_info' declared inside parameter list will not be visible outside of this definition or declaration
      30 |                                        struct ftrace_info *psinfo)
         |                                               ^~~~~~~~~~~
   fs/pstore/ftrace.c: In function 'pstore_do_ftrace':
>> fs/pstore/ftrace.c:39:24: error: initialization of 'struct pstore_info *' from incompatible pointer type 'struct ftrace_info *' [-Werror=incompatible-pointer-types]
      39 |                 .psi = psinfo,
         |                        ^~~~~~
   fs/pstore/ftrace.c:39:24: note: (near initialization for 'record.psi')
>> fs/pstore/ftrace.c:55:15: error: invalid use of undefined type 'struct ftrace_info'
      55 |         psinfo->write(&record);
         |               ^~
   fs/pstore/ftrace.c: In function 'pstore_ftrace_call':
>> fs/pstore/ftrace.c:71:61: error: passing argument 4 of 'pstore_do_ftrace' from incompatible pointer type [-Werror=incompatible-pointer-types]
      71 |                         pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
         |                                                             ^~~~
         |                                                             |
         |                                                             struct pt_regs *
   fs/pstore/ftrace.c:29:60: note: expected 'struct ftrace_regs *' but argument is of type 'struct pt_regs *'
      29 |                                        struct ftrace_regs *fregs,
         |                                        ~~~~~~~~~~~~~~~~~~~~^~~~~
   fs/pstore/ftrace.c:71:72: error: passing argument 5 of 'pstore_do_ftrace' from incompatible pointer type [-Werror=incompatible-pointer-types]
      71 |                         pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
         |                                                                   ~~~~~^~~~~
         |                                                                        |
         |                                                                        struct pstore_info *
   fs/pstore/ftrace.c:30:60: note: expected 'struct ftrace_info *' but argument is of type 'struct pstore_info *'
      30 |                                        struct ftrace_info *psinfo)
         |                                        ~~~~~~~~~~~~~~~~~~~~^~~~~~
   fs/pstore/ftrace.c: At top level:
>> fs/pstore/ftrace.c:76:19: error: initialization of 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' from incompatible pointer type 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct pt_regs *)' [-Werror=incompatible-pointer-types]
      76 |         .func   = pstore_ftrace_call,
         |                   ^~~~~~~~~~~~~~~~~~
   fs/pstore/ftrace.c:76:19: note: (near initialization for 'pstore_ftrace_ops.func')
   In file included from include/linux/dcache.h:8,
                    from include/linux/fs.h:8,
                    from include/linux/huge_mm.h:8,
                    from include/linux/mm.h:1095,
                    from include/linux/kallsyms.h:13,
                    from include/linux/ftrace.h:13,
                    from fs/pstore/ftrace.c:14:
   fs/pstore/ftrace.c: In function 'pstore_register_ftrace':
>> fs/pstore/ftrace.c:150:33: error: 'entry' undeclared (first use in this function); did you mean 'dentry'?
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |                                 ^~~~~
   include/linux/rculist.h:391:14: note: in definition of macro 'list_for_each_entry_rcu'
     391 |              pos = list_entry_rcu((head)->next, typeof(*pos), member);  \
         |              ^~~
   fs/pstore/ftrace.c:150:33: note: each undeclared identifier is reported only once for each function it appears in
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |                                 ^~~~~
   include/linux/rculist.h:391:14: note: in definition of macro 'list_for_each_entry_rcu'
     391 |              pos = list_entry_rcu((head)->next, typeof(*pos), member);  \
         |              ^~~
   In file included from include/linux/container_of.h:5,
                    from include/linux/kernel.h:22,
                    from fs/pstore/ftrace.c:6:
   include/linux/compiler_types.h:376:27: error: expression in static assertion is not an integer
     376 | #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
         |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   include/linux/container_of.h:20:9: note: in expansion of macro 'static_assert'
      20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
         |         ^~~~~~~~~~~~~
   include/linux/container_of.h:20:23: note: in expansion of macro '__same_type'
      20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
         |                       ^~~~~~~~~~~
   include/linux/rculist.h:307:9: note: in expansion of macro 'container_of'
     307 |         container_of(READ_ONCE(ptr), type, member)
         |         ^~~~~~~~~~~~
   include/linux/rculist.h:391:20: note: in expansion of macro 'list_entry_rcu'
     391 |              pos = list_entry_rcu((head)->next, typeof(*pos), member);  \
         |                    ^~~~~~~~~~~~~~
   fs/pstore/ftrace.c:150:9: note: in expansion of macro 'list_for_each_entry_rcu'
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler_types.h:376:27: error: expression in static assertion is not an integer
     376 | #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
         |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   include/linux/container_of.h:20:9: note: in expansion of macro 'static_assert'
      20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
         |         ^~~~~~~~~~~~~
   include/linux/container_of.h:20:23: note: in expansion of macro '__same_type'
      20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
         |                       ^~~~~~~~~~~
   include/linux/rculist.h:307:9: note: in expansion of macro 'container_of'
     307 |         container_of(READ_ONCE(ptr), type, member)
         |         ^~~~~~~~~~~~
   include/linux/rculist.h:393:23: note: in expansion of macro 'list_entry_rcu'
     393 |                 pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
         |                       ^~~~~~~~~~~~~~
   fs/pstore/ftrace.c:150:9: note: in expansion of macro 'list_for_each_entry_rcu'
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +39 fs/pstore/ftrace.c

fbccdeb8d77d68 Joel Fernandes          2016-10-20   25  
7b968e55e3984c Yuanhe Shu              2024-02-05   26  static void notrace pstore_do_ftrace(unsigned long ip,
ebacfd1ece3bfa Anton Vorontsov         2012-11-14   27  				       unsigned long parent_ip,
ebacfd1ece3bfa Anton Vorontsov         2012-11-14   28  				       struct ftrace_ops *op,
7b968e55e3984c Yuanhe Shu              2024-02-05   29  				       struct ftrace_regs *fregs,
7b968e55e3984c Yuanhe Shu              2024-02-05  @30  				       struct ftrace_info *psinfo)
060287b8c467bf Anton Vorontsov         2012-07-09   31  {
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   32) 	int bit;
65f8c95e46a182 Anton Vorontsov         2012-07-17   33  	unsigned long flags;
060287b8c467bf Anton Vorontsov         2012-07-09   34  	struct pstore_ftrace_record rec = {};
b10b471145f28c Kees Cook               2017-03-05   35  	struct pstore_record record = {
b10b471145f28c Kees Cook               2017-03-05   36  		.type = PSTORE_TYPE_FTRACE,
b10b471145f28c Kees Cook               2017-03-05   37  		.buf = (char *)&rec,
b10b471145f28c Kees Cook               2017-03-05   38  		.size = sizeof(rec),
b10b471145f28c Kees Cook               2017-03-05  @39  		.psi = psinfo,
b10b471145f28c Kees Cook               2017-03-05   40  	};
060287b8c467bf Anton Vorontsov         2012-07-09   41  
060287b8c467bf Anton Vorontsov         2012-07-09   42  	if (unlikely(oops_in_progress))
060287b8c467bf Anton Vorontsov         2012-07-09   43  		return;
060287b8c467bf Anton Vorontsov         2012-07-09   44  
773c16705058e9 Steven Rostedt (VMware  2020-11-05   45) 	bit = ftrace_test_recursion_trylock(ip, parent_ip);
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   46) 	if (bit < 0)
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   47) 		return;
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   48) 
65f8c95e46a182 Anton Vorontsov         2012-07-17   49  	local_irq_save(flags);
65f8c95e46a182 Anton Vorontsov         2012-07-17   50  
060287b8c467bf Anton Vorontsov         2012-07-09   51  	rec.ip = ip;
060287b8c467bf Anton Vorontsov         2012-07-09   52  	rec.parent_ip = parent_ip;
fbccdeb8d77d68 Joel Fernandes          2016-10-20   53  	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
060287b8c467bf Anton Vorontsov         2012-07-09   54  	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
4c9ec219766a21 Kees Cook               2017-03-05  @55  	psinfo->write(&record);
65f8c95e46a182 Anton Vorontsov         2012-07-17   56  
65f8c95e46a182 Anton Vorontsov         2012-07-17   57  	local_irq_restore(flags);
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   58) 	ftrace_test_recursion_unlock(bit);
65f8c95e46a182 Anton Vorontsov         2012-07-17   59  }
65f8c95e46a182 Anton Vorontsov         2012-07-17   60  
7b968e55e3984c Yuanhe Shu              2024-02-05   61  static void notrace pstore_ftrace_call(unsigned long ip,
7b968e55e3984c Yuanhe Shu              2024-02-05   62  				       unsigned long parent_ip,
7b968e55e3984c Yuanhe Shu              2024-02-05   63  				       struct ftrace_ops *op,
7b968e55e3984c Yuanhe Shu              2024-02-05   64  				       struct pt_regs *regs)
7b968e55e3984c Yuanhe Shu              2024-02-05   65  {
7b968e55e3984c Yuanhe Shu              2024-02-05   66  	struct pstore_info_list *entry;
7b968e55e3984c Yuanhe Shu              2024-02-05   67  
7b968e55e3984c Yuanhe Shu              2024-02-05   68  	rcu_read_lock();
7b968e55e3984c Yuanhe Shu              2024-02-05   69  	list_for_each_entry_rcu(entry, &psback->list_entry, list)
7b968e55e3984c Yuanhe Shu              2024-02-05   70  		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
7b968e55e3984c Yuanhe Shu              2024-02-05  @71  			pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
7b968e55e3984c Yuanhe Shu              2024-02-05   72  	rcu_read_unlock();
7b968e55e3984c Yuanhe Shu              2024-02-05   73  }
7b968e55e3984c Yuanhe Shu              2024-02-05   74  
65f8c95e46a182 Anton Vorontsov         2012-07-17   75  static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
65f8c95e46a182 Anton Vorontsov         2012-07-17  @76  	.func	= pstore_ftrace_call,
65f8c95e46a182 Anton Vorontsov         2012-07-17   77  };
65f8c95e46a182 Anton Vorontsov         2012-07-17   78  
65f8c95e46a182 Anton Vorontsov         2012-07-17   79  static DEFINE_MUTEX(pstore_ftrace_lock);
65f8c95e46a182 Anton Vorontsov         2012-07-17   80  static bool pstore_ftrace_enabled;
65f8c95e46a182 Anton Vorontsov         2012-07-17   81  
a5d05b07961a2d Uwe Kleine-König        2021-06-10   82  static int pstore_set_ftrace_enabled(bool on)
65f8c95e46a182 Anton Vorontsov         2012-07-17   83  {
65f8c95e46a182 Anton Vorontsov         2012-07-17   84  	ssize_t ret;
65f8c95e46a182 Anton Vorontsov         2012-07-17   85  
a5d05b07961a2d Uwe Kleine-König        2021-06-10   86  	if (on == pstore_ftrace_enabled)
a5d05b07961a2d Uwe Kleine-König        2021-06-10   87  		return 0;
65f8c95e46a182 Anton Vorontsov         2012-07-17   88  
7a0032f50472c7 Joel Fernandes          2016-11-15   89  	if (on) {
7a0032f50472c7 Joel Fernandes          2016-11-15   90  		ftrace_ops_set_global_filter(&pstore_ftrace_ops);
65f8c95e46a182 Anton Vorontsov         2012-07-17   91  		ret = register_ftrace_function(&pstore_ftrace_ops);
7a0032f50472c7 Joel Fernandes          2016-11-15   92  	} else {
65f8c95e46a182 Anton Vorontsov         2012-07-17   93  		ret = unregister_ftrace_function(&pstore_ftrace_ops);
7a0032f50472c7 Joel Fernandes          2016-11-15   94  	}
7a0032f50472c7 Joel Fernandes          2016-11-15   95  
65f8c95e46a182 Anton Vorontsov         2012-07-17   96  	if (ret) {
65f8c95e46a182 Anton Vorontsov         2012-07-17   97  		pr_err("%s: unable to %sregister ftrace ops: %zd\n",
65f8c95e46a182 Anton Vorontsov         2012-07-17   98  		       __func__, on ? "" : "un", ret);
a5d05b07961a2d Uwe Kleine-König        2021-06-10   99  	} else {
a5d05b07961a2d Uwe Kleine-König        2021-06-10  100  		pstore_ftrace_enabled = on;
65f8c95e46a182 Anton Vorontsov         2012-07-17  101  	}
65f8c95e46a182 Anton Vorontsov         2012-07-17  102  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  103  	return ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  104  }
a5d05b07961a2d Uwe Kleine-König        2021-06-10  105  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  106  static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
a5d05b07961a2d Uwe Kleine-König        2021-06-10  107  					size_t count, loff_t *ppos)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  108  {
a5d05b07961a2d Uwe Kleine-König        2021-06-10  109  	u8 on;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  110  	ssize_t ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  111  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  112  	ret = kstrtou8_from_user(buf, count, 2, &on);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  113  	if (ret)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  114  		return ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  115  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  116  	mutex_lock(&pstore_ftrace_lock);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  117  	ret = pstore_set_ftrace_enabled(on);
65f8c95e46a182 Anton Vorontsov         2012-07-17  118  	mutex_unlock(&pstore_ftrace_lock);
65f8c95e46a182 Anton Vorontsov         2012-07-17  119  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  120  	if (ret == 0)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  121  		ret = count;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  122  
65f8c95e46a182 Anton Vorontsov         2012-07-17  123  	return ret;
65f8c95e46a182 Anton Vorontsov         2012-07-17  124  }
65f8c95e46a182 Anton Vorontsov         2012-07-17  125  
65f8c95e46a182 Anton Vorontsov         2012-07-17  126  static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
65f8c95e46a182 Anton Vorontsov         2012-07-17  127  				       size_t count, loff_t *ppos)
65f8c95e46a182 Anton Vorontsov         2012-07-17  128  {
65f8c95e46a182 Anton Vorontsov         2012-07-17  129  	char val[] = { '0' + pstore_ftrace_enabled, '\n' };
65f8c95e46a182 Anton Vorontsov         2012-07-17  130  
65f8c95e46a182 Anton Vorontsov         2012-07-17  131  	return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
65f8c95e46a182 Anton Vorontsov         2012-07-17  132  }
65f8c95e46a182 Anton Vorontsov         2012-07-17  133  
65f8c95e46a182 Anton Vorontsov         2012-07-17  134  static const struct file_operations pstore_knob_fops = {
65f8c95e46a182 Anton Vorontsov         2012-07-17  135  	.open	= simple_open,
65f8c95e46a182 Anton Vorontsov         2012-07-17  136  	.read	= pstore_ftrace_knob_read,
65f8c95e46a182 Anton Vorontsov         2012-07-17  137  	.write	= pstore_ftrace_knob_write,
65f8c95e46a182 Anton Vorontsov         2012-07-17  138  };
65f8c95e46a182 Anton Vorontsov         2012-07-17  139  
ee1d267423a1f8 Geliang Tang            2015-10-20  140  static struct dentry *pstore_ftrace_dir;
ee1d267423a1f8 Geliang Tang            2015-10-20  141  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  142  static bool record_ftrace;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  143  module_param(record_ftrace, bool, 0400);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  144  MODULE_PARM_DESC(record_ftrace,
a5d05b07961a2d Uwe Kleine-König        2021-06-10  145  		 "enable ftrace recording immediately (default: off)");
a5d05b07961a2d Uwe Kleine-König        2021-06-10  146  
65f8c95e46a182 Anton Vorontsov         2012-07-17  147  void pstore_register_ftrace(void)
65f8c95e46a182 Anton Vorontsov         2012-07-17  148  {
7b968e55e3984c Yuanhe Shu              2024-02-05  149  	rcu_read_lock();
7b968e55e3984c Yuanhe Shu              2024-02-05 @150  	list_for_each_entry_rcu(entry, &psback->list_entry, list)
7b968e55e3984c Yuanhe Shu              2024-02-05  151  		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
7b968e55e3984c Yuanhe Shu              2024-02-05  152  			if (!entry->psi->write) {
7b968e55e3984c Yuanhe Shu              2024-02-05  153  				rcu_read_unlock();
65f8c95e46a182 Anton Vorontsov         2012-07-17  154  				return;
7b968e55e3984c Yuanhe Shu              2024-02-05  155  			}
7b968e55e3984c Yuanhe Shu              2024-02-05  156  	rcu_read_unlock();
65f8c95e46a182 Anton Vorontsov         2012-07-17  157  
ee1d267423a1f8 Geliang Tang            2015-10-20  158  	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
65f8c95e46a182 Anton Vorontsov         2012-07-17  159  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  160  	pstore_set_ftrace_enabled(record_ftrace);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  161  
fa1af7583e8012 Greg Kroah-Hartman      2019-06-12  162  	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
fa1af7583e8012 Greg Kroah-Hartman      2019-06-12  163  			    &pstore_knob_fops);
ee1d267423a1f8 Geliang Tang            2015-10-20  164  }
ee1d267423a1f8 Geliang Tang            2015-10-20  165
  
kernel test robot Feb. 6, 2024, 12:17 p.m. UTC | #2
Hi Yuanhe,

kernel test robot noticed the following build errors:

[auto build test ERROR on kees/for-next/pstore]
[also build test ERROR on kees/for-next/kspp shuah-kselftest/next shuah-kselftest/fixes linus/master v6.8-rc3 next-20240206]
[cannot apply to aegl/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Yuanhe-Shu/pstore-add-multi-backend-support/20240205-203438
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
patch link:    https://lore.kernel.org/r/20240205122852.7069-2-xiangzao%40linux.alibaba.com
patch subject: [PATCH 1/3] pstore: add multi-backend support
config: i386-buildonly-randconfig-004-20240206 (https://download.01.org/0day-ci/archive/20240206/202402062036.5FPFKsGI-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240206/202402062036.5FPFKsGI-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402062036.5FPFKsGI-lkp@intel.com/

All errors (new ones prefixed by >>):

   fs/pstore/ftrace.c:30:19: warning: declaration of 'struct ftrace_info' will not be visible outside of this function [-Wvisibility]
      30 |                                        struct ftrace_info *psinfo)
         |                                               ^
>> fs/pstore/ftrace.c:39:10: error: incompatible pointer types initializing 'struct pstore_info *' with an expression of type 'struct ftrace_info *' [-Werror,-Wincompatible-pointer-types]
      39 |                 .psi = psinfo,
         |                        ^~~~~~
>> fs/pstore/ftrace.c:55:8: error: incomplete definition of type 'struct ftrace_info'
      55 |         psinfo->write(&record);
         |         ~~~~~~^
   fs/pstore/ftrace.c:30:19: note: forward declaration of 'struct ftrace_info'
      30 |                                        struct ftrace_info *psinfo)
         |                                               ^
>> fs/pstore/ftrace.c:71:40: error: incompatible pointer types passing 'struct pt_regs *' to parameter of type 'struct ftrace_regs *' [-Werror,-Wincompatible-pointer-types]
      71 |                         pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
         |                                                             ^~~~
   fs/pstore/ftrace.c:29:32: note: passing argument to parameter 'fregs' here
      29 |                                        struct ftrace_regs *fregs,
         |                                                            ^
>> fs/pstore/ftrace.c:71:46: error: incompatible pointer types passing 'struct pstore_info *' to parameter of type 'struct ftrace_info *' [-Werror,-Wincompatible-pointer-types]
      71 |                         pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
         |                                                                   ^~~~~~~~~~
   fs/pstore/ftrace.c:30:32: note: passing argument to parameter 'psinfo' here
      30 |                                        struct ftrace_info *psinfo)
         |                                                            ^
>> fs/pstore/ftrace.c:76:10: error: incompatible function pointer types initializing 'ftrace_func_t' (aka 'void (*)(unsigned long, unsigned long, struct ftrace_ops *, struct ftrace_regs *)') with an expression of type 'void (unsigned long, unsigned long, struct ftrace_ops *, struct pt_regs *)' [-Wincompatible-function-pointer-types]
      76 |         .func   = pstore_ftrace_call,
         |                   ^~~~~~~~~~~~~~~~~~
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |                                 ^
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
>> fs/pstore/ftrace.c:150:2: error: operand of type 'void' where arithmetic or pointer type is required
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/rculist.h:393:9: note: expanded from macro 'list_for_each_entry_rcu'
     393 |                 pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/rculist.h:307:2: note: expanded from macro 'list_entry_rcu'
     307 |         container_of(READ_ONCE(ptr), type, member)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/container_of.h:19:25: note: expanded from macro 'container_of'
      19 |         void *__mptr = (void *)(ptr);                                   \
         |                                ^~~~~
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
     150 |         list_for_each_entry_rcu(entry, &psback->list_entry, list)
         |                                 ^
>> fs/pstore/ftrace.c:150:26: error: use of undeclared identifier 'entry'
   fatal error: too many errors emitted, stopping now [-ferror-limit=]
   1 warning and 20 errors generated.


vim +39 fs/pstore/ftrace.c

fbccdeb8d77d68 Joel Fernandes          2016-10-20   25  
7b968e55e3984c Yuanhe Shu              2024-02-05   26  static void notrace pstore_do_ftrace(unsigned long ip,
ebacfd1ece3bfa Anton Vorontsov         2012-11-14   27  				       unsigned long parent_ip,
ebacfd1ece3bfa Anton Vorontsov         2012-11-14   28  				       struct ftrace_ops *op,
7b968e55e3984c Yuanhe Shu              2024-02-05   29  				       struct ftrace_regs *fregs,
7b968e55e3984c Yuanhe Shu              2024-02-05   30  				       struct ftrace_info *psinfo)
060287b8c467bf Anton Vorontsov         2012-07-09   31  {
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   32) 	int bit;
65f8c95e46a182 Anton Vorontsov         2012-07-17   33  	unsigned long flags;
060287b8c467bf Anton Vorontsov         2012-07-09   34  	struct pstore_ftrace_record rec = {};
b10b471145f28c Kees Cook               2017-03-05   35  	struct pstore_record record = {
b10b471145f28c Kees Cook               2017-03-05   36  		.type = PSTORE_TYPE_FTRACE,
b10b471145f28c Kees Cook               2017-03-05   37  		.buf = (char *)&rec,
b10b471145f28c Kees Cook               2017-03-05   38  		.size = sizeof(rec),
b10b471145f28c Kees Cook               2017-03-05  @39  		.psi = psinfo,
b10b471145f28c Kees Cook               2017-03-05   40  	};
060287b8c467bf Anton Vorontsov         2012-07-09   41  
060287b8c467bf Anton Vorontsov         2012-07-09   42  	if (unlikely(oops_in_progress))
060287b8c467bf Anton Vorontsov         2012-07-09   43  		return;
060287b8c467bf Anton Vorontsov         2012-07-09   44  
773c16705058e9 Steven Rostedt (VMware  2020-11-05   45) 	bit = ftrace_test_recursion_trylock(ip, parent_ip);
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   46) 	if (bit < 0)
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   47) 		return;
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   48) 
65f8c95e46a182 Anton Vorontsov         2012-07-17   49  	local_irq_save(flags);
65f8c95e46a182 Anton Vorontsov         2012-07-17   50  
060287b8c467bf Anton Vorontsov         2012-07-09   51  	rec.ip = ip;
060287b8c467bf Anton Vorontsov         2012-07-09   52  	rec.parent_ip = parent_ip;
fbccdeb8d77d68 Joel Fernandes          2016-10-20   53  	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
060287b8c467bf Anton Vorontsov         2012-07-09   54  	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
4c9ec219766a21 Kees Cook               2017-03-05  @55  	psinfo->write(&record);
65f8c95e46a182 Anton Vorontsov         2012-07-17   56  
65f8c95e46a182 Anton Vorontsov         2012-07-17   57  	local_irq_restore(flags);
6cdf941871ec9c Steven Rostedt (VMware  2020-11-05   58) 	ftrace_test_recursion_unlock(bit);
65f8c95e46a182 Anton Vorontsov         2012-07-17   59  }
65f8c95e46a182 Anton Vorontsov         2012-07-17   60  
7b968e55e3984c Yuanhe Shu              2024-02-05   61  static void notrace pstore_ftrace_call(unsigned long ip,
7b968e55e3984c Yuanhe Shu              2024-02-05   62  				       unsigned long parent_ip,
7b968e55e3984c Yuanhe Shu              2024-02-05   63  				       struct ftrace_ops *op,
7b968e55e3984c Yuanhe Shu              2024-02-05   64  				       struct pt_regs *regs)
7b968e55e3984c Yuanhe Shu              2024-02-05   65  {
7b968e55e3984c Yuanhe Shu              2024-02-05   66  	struct pstore_info_list *entry;
7b968e55e3984c Yuanhe Shu              2024-02-05   67  
7b968e55e3984c Yuanhe Shu              2024-02-05   68  	rcu_read_lock();
7b968e55e3984c Yuanhe Shu              2024-02-05   69  	list_for_each_entry_rcu(entry, &psback->list_entry, list)
7b968e55e3984c Yuanhe Shu              2024-02-05   70  		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
7b968e55e3984c Yuanhe Shu              2024-02-05  @71  			pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
7b968e55e3984c Yuanhe Shu              2024-02-05   72  	rcu_read_unlock();
7b968e55e3984c Yuanhe Shu              2024-02-05   73  }
7b968e55e3984c Yuanhe Shu              2024-02-05   74  
65f8c95e46a182 Anton Vorontsov         2012-07-17   75  static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
65f8c95e46a182 Anton Vorontsov         2012-07-17  @76  	.func	= pstore_ftrace_call,
65f8c95e46a182 Anton Vorontsov         2012-07-17   77  };
65f8c95e46a182 Anton Vorontsov         2012-07-17   78  
65f8c95e46a182 Anton Vorontsov         2012-07-17   79  static DEFINE_MUTEX(pstore_ftrace_lock);
65f8c95e46a182 Anton Vorontsov         2012-07-17   80  static bool pstore_ftrace_enabled;
65f8c95e46a182 Anton Vorontsov         2012-07-17   81  
a5d05b07961a2d Uwe Kleine-König        2021-06-10   82  static int pstore_set_ftrace_enabled(bool on)
65f8c95e46a182 Anton Vorontsov         2012-07-17   83  {
65f8c95e46a182 Anton Vorontsov         2012-07-17   84  	ssize_t ret;
65f8c95e46a182 Anton Vorontsov         2012-07-17   85  
a5d05b07961a2d Uwe Kleine-König        2021-06-10   86  	if (on == pstore_ftrace_enabled)
a5d05b07961a2d Uwe Kleine-König        2021-06-10   87  		return 0;
65f8c95e46a182 Anton Vorontsov         2012-07-17   88  
7a0032f50472c7 Joel Fernandes          2016-11-15   89  	if (on) {
7a0032f50472c7 Joel Fernandes          2016-11-15   90  		ftrace_ops_set_global_filter(&pstore_ftrace_ops);
65f8c95e46a182 Anton Vorontsov         2012-07-17   91  		ret = register_ftrace_function(&pstore_ftrace_ops);
7a0032f50472c7 Joel Fernandes          2016-11-15   92  	} else {
65f8c95e46a182 Anton Vorontsov         2012-07-17   93  		ret = unregister_ftrace_function(&pstore_ftrace_ops);
7a0032f50472c7 Joel Fernandes          2016-11-15   94  	}
7a0032f50472c7 Joel Fernandes          2016-11-15   95  
65f8c95e46a182 Anton Vorontsov         2012-07-17   96  	if (ret) {
65f8c95e46a182 Anton Vorontsov         2012-07-17   97  		pr_err("%s: unable to %sregister ftrace ops: %zd\n",
65f8c95e46a182 Anton Vorontsov         2012-07-17   98  		       __func__, on ? "" : "un", ret);
a5d05b07961a2d Uwe Kleine-König        2021-06-10   99  	} else {
a5d05b07961a2d Uwe Kleine-König        2021-06-10  100  		pstore_ftrace_enabled = on;
65f8c95e46a182 Anton Vorontsov         2012-07-17  101  	}
65f8c95e46a182 Anton Vorontsov         2012-07-17  102  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  103  	return ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  104  }
a5d05b07961a2d Uwe Kleine-König        2021-06-10  105  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  106  static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
a5d05b07961a2d Uwe Kleine-König        2021-06-10  107  					size_t count, loff_t *ppos)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  108  {
a5d05b07961a2d Uwe Kleine-König        2021-06-10  109  	u8 on;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  110  	ssize_t ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  111  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  112  	ret = kstrtou8_from_user(buf, count, 2, &on);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  113  	if (ret)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  114  		return ret;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  115  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  116  	mutex_lock(&pstore_ftrace_lock);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  117  	ret = pstore_set_ftrace_enabled(on);
65f8c95e46a182 Anton Vorontsov         2012-07-17  118  	mutex_unlock(&pstore_ftrace_lock);
65f8c95e46a182 Anton Vorontsov         2012-07-17  119  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  120  	if (ret == 0)
a5d05b07961a2d Uwe Kleine-König        2021-06-10  121  		ret = count;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  122  
65f8c95e46a182 Anton Vorontsov         2012-07-17  123  	return ret;
65f8c95e46a182 Anton Vorontsov         2012-07-17  124  }
65f8c95e46a182 Anton Vorontsov         2012-07-17  125  
65f8c95e46a182 Anton Vorontsov         2012-07-17  126  static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
65f8c95e46a182 Anton Vorontsov         2012-07-17  127  				       size_t count, loff_t *ppos)
65f8c95e46a182 Anton Vorontsov         2012-07-17  128  {
65f8c95e46a182 Anton Vorontsov         2012-07-17  129  	char val[] = { '0' + pstore_ftrace_enabled, '\n' };
65f8c95e46a182 Anton Vorontsov         2012-07-17  130  
65f8c95e46a182 Anton Vorontsov         2012-07-17  131  	return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
65f8c95e46a182 Anton Vorontsov         2012-07-17  132  }
65f8c95e46a182 Anton Vorontsov         2012-07-17  133  
65f8c95e46a182 Anton Vorontsov         2012-07-17  134  static const struct file_operations pstore_knob_fops = {
65f8c95e46a182 Anton Vorontsov         2012-07-17  135  	.open	= simple_open,
65f8c95e46a182 Anton Vorontsov         2012-07-17  136  	.read	= pstore_ftrace_knob_read,
65f8c95e46a182 Anton Vorontsov         2012-07-17  137  	.write	= pstore_ftrace_knob_write,
65f8c95e46a182 Anton Vorontsov         2012-07-17  138  };
65f8c95e46a182 Anton Vorontsov         2012-07-17  139  
ee1d267423a1f8 Geliang Tang            2015-10-20  140  static struct dentry *pstore_ftrace_dir;
ee1d267423a1f8 Geliang Tang            2015-10-20  141  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  142  static bool record_ftrace;
a5d05b07961a2d Uwe Kleine-König        2021-06-10  143  module_param(record_ftrace, bool, 0400);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  144  MODULE_PARM_DESC(record_ftrace,
a5d05b07961a2d Uwe Kleine-König        2021-06-10  145  		 "enable ftrace recording immediately (default: off)");
a5d05b07961a2d Uwe Kleine-König        2021-06-10  146  
65f8c95e46a182 Anton Vorontsov         2012-07-17  147  void pstore_register_ftrace(void)
65f8c95e46a182 Anton Vorontsov         2012-07-17  148  {
7b968e55e3984c Yuanhe Shu              2024-02-05  149  	rcu_read_lock();
7b968e55e3984c Yuanhe Shu              2024-02-05 @150  	list_for_each_entry_rcu(entry, &psback->list_entry, list)
7b968e55e3984c Yuanhe Shu              2024-02-05  151  		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
7b968e55e3984c Yuanhe Shu              2024-02-05  152  			if (!entry->psi->write) {
7b968e55e3984c Yuanhe Shu              2024-02-05  153  				rcu_read_unlock();
65f8c95e46a182 Anton Vorontsov         2012-07-17  154  				return;
7b968e55e3984c Yuanhe Shu              2024-02-05  155  			}
7b968e55e3984c Yuanhe Shu              2024-02-05  156  	rcu_read_unlock();
65f8c95e46a182 Anton Vorontsov         2012-07-17  157  
ee1d267423a1f8 Geliang Tang            2015-10-20  158  	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
65f8c95e46a182 Anton Vorontsov         2012-07-17  159  
a5d05b07961a2d Uwe Kleine-König        2021-06-10  160  	pstore_set_ftrace_enabled(record_ftrace);
a5d05b07961a2d Uwe Kleine-König        2021-06-10  161  
fa1af7583e8012 Greg Kroah-Hartman      2019-06-12  162  	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
fa1af7583e8012 Greg Kroah-Hartman      2019-06-12  163  			    &pstore_knob_fops);
ee1d267423a1f8 Geliang Tang            2015-10-20  164  }
ee1d267423a1f8 Geliang Tang            2015-10-20  165
  

Patch

diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index 776cae20af4e..2532a663aa2c 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -23,10 +23,11 @@ 
 /* This doesn't need to be atomic: speed is chosen over correctness here. */
 static u64 pstore_ftrace_stamp;
 
-static void notrace pstore_ftrace_call(unsigned long ip,
+static void notrace pstore_do_ftrace(unsigned long ip,
 				       unsigned long parent_ip,
 				       struct ftrace_ops *op,
-				       struct ftrace_regs *fregs)
+				       struct ftrace_regs *fregs,
+				       struct ftrace_info *psinfo)
 {
 	int bit;
 	unsigned long flags;
@@ -57,6 +58,20 @@  static void notrace pstore_ftrace_call(unsigned long ip,
 	ftrace_test_recursion_unlock(bit);
 }
 
+static void notrace pstore_ftrace_call(unsigned long ip,
+				       unsigned long parent_ip,
+				       struct ftrace_ops *op,
+				       struct pt_regs *regs)
+{
+	struct pstore_info_list *entry;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &psback->list_entry, list)
+		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
+			pstore_do_ftrace(ip, parent_ip, op, regs, entry->psi);
+	rcu_read_unlock();
+}
+
 static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
 	.func	= pstore_ftrace_call,
 };
@@ -131,8 +146,14 @@  MODULE_PARM_DESC(record_ftrace,
 
 void pstore_register_ftrace(void)
 {
-	if (!psinfo->write)
-		return;
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &psback->list_entry, list)
+		if (entry->psi->flags & PSTORE_FLAGS_FTRACE)
+			if (!entry->psi->write) {
+				rcu_read_unlock();
+				return;
+			}
+	rcu_read_unlock();
 
 	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
 
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index d0d9bfdad30c..bee71c7da995 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -285,7 +285,7 @@  static const struct super_operations pstore_ops = {
 	.show_options	= pstore_show_options,
 };
 
-static struct dentry *psinfo_lock_root(void)
+static struct dentry *psinfo_lock_root(struct pstore_info *psinfo)
 {
 	struct dentry *root;
 
@@ -309,7 +309,7 @@  int pstore_put_backend_records(struct pstore_info *psi)
 	struct dentry *root;
 	int rc = 0;
 
-	root = psinfo_lock_root();
+	root = psinfo_lock_root(psi);
 	if (!root)
 		return 0;
 
@@ -398,21 +398,22 @@  int pstore_mkfile(struct dentry *root, struct pstore_record *record)
  * when we are re-scanning the backing store looking to add new
  * error records.
  */
-void pstore_get_records(int quiet)
+void pstore_get_records(struct pstore_info *psi, int quiet)
 {
 	struct dentry *root;
 
-	root = psinfo_lock_root();
+	root = psinfo_lock_root(psi);
 	if (!root)
 		return;
 
-	pstore_get_backend_records(psinfo, root, quiet);
+	pstore_get_backend_records(psi, root, quiet);
 	inode_unlock(d_inode(root));
 }
 
 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *inode;
+	struct pstore_info_list *entry;
 
 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
 	sb->s_blocksize		= PAGE_SIZE;
@@ -437,7 +438,13 @@  static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 	scoped_guard(mutex, &pstore_sb_lock)
 		pstore_sb = sb;
 
-	pstore_get_records(0);
+	if (!psback)
+		return 0;
+
+	mutex_lock(&psback_lock);
+	list_for_each_entry(entry, &psback->list_entry, list)
+		pstore_get_records(entry->psi, 0);
+	mutex_unlock(&psback_lock);
 
 	return 0;
 }
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 801d6c0b170c..4b1c7ba27052 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -33,10 +33,10 @@  static inline void pstore_register_pmsg(void) {}
 static inline void pstore_unregister_pmsg(void) {}
 #endif
 
-extern struct pstore_info *psinfo;
+extern struct pstore_backends *psback;
 
 extern void	pstore_set_kmsg_bytes(int);
-extern void	pstore_get_records(int);
+extern void	pstore_get_records(struct pstore_info *psi, int quiet);
 extern void	pstore_get_backend_records(struct pstore_info *psi,
 					   struct dentry *root, int quiet);
 extern int	pstore_put_backend_records(struct pstore_info *psi);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 03425928d2fb..432a41852a07 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -62,12 +62,12 @@  static void pstore_dowork(struct work_struct *);
 static DECLARE_WORK(pstore_work, pstore_dowork);
 
 /*
- * psinfo_lock protects "psinfo" during calls to
+ * psback_lock protects "psback" during calls to
  * pstore_register(), pstore_unregister(), and
  * the filesystem mount/unmount routines.
  */
-static DEFINE_MUTEX(psinfo_lock);
-struct pstore_info *psinfo;
+DEFINE_MUTEX(psback_lock);
+struct pstore_backends *psback;
 
 static char *backend;
 module_param(backend, charp, 0444);
@@ -104,7 +104,7 @@  static void *compress_workspace;
  */
 #define DMESG_COMP_PERCENT	60
 
-static char *big_oops_buf;
+static char *big_oops_buf[PSTORE_BACKEND_NUM];
 static size_t max_compressed_size;
 
 void pstore_set_kmsg_bytes(int bytes)
@@ -201,7 +201,7 @@  static int pstore_compress(const void *in, void *out,
 	return zstream.total_out;
 }
 
-static void allocate_buf_for_compression(void)
+static void allocate_buf_for_compression(struct pstore_info *psinfo, int pos)
 {
 	size_t compressed_size;
 	char *buf;
@@ -241,21 +241,21 @@  static void allocate_buf_for_compression(void)
 	}
 
 	/* A non-NULL big_oops_buf indicates compression is available. */
-	big_oops_buf = buf;
+	big_oops_buf[pos] = buf;
 	max_compressed_size = compressed_size;
 
 	pr_info("Using crash dump compression: %s\n", compress);
 }
 
-static void free_buf_for_compression(void)
+static void free_buf_for_compression(int pos)
 {
 	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) {
 		vfree(compress_workspace);
 		compress_workspace = NULL;
 	}
 
-	kvfree(big_oops_buf);
-	big_oops_buf = NULL;
+	kvfree(big_oops_buf[pos]);
+	big_oops_buf[pos] = NULL;
 	max_compressed_size = 0;
 }
 
@@ -274,8 +274,9 @@  void pstore_record_init(struct pstore_record *record,
  * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
  * end of the buffer.
  */
-static void pstore_dump(struct kmsg_dumper *dumper,
-			enum kmsg_dump_reason reason)
+static void pstore_do_dump(struct kmsg_dumper *dumper,
+			enum kmsg_dump_reason reason,
+			struct pstore_info *psinfo, int pos)
 {
 	struct kmsg_dump_iter iter;
 	unsigned long	total = 0;
@@ -315,7 +316,7 @@  static void pstore_dump(struct kmsg_dumper *dumper,
 		record.part = part;
 		record.buf = psinfo->buf;
 
-		dst = big_oops_buf ?: psinfo->buf;
+		dst = big_oops_buf[pos] ?: psinfo->buf;
 		dst_size = max_compressed_size ?: psinfo->bufsize;
 
 		/* Write dump header. */
@@ -328,7 +329,7 @@  static void pstore_dump(struct kmsg_dumper *dumper,
 					  dst_size, &dump_size))
 			break;
 
-		if (big_oops_buf) {
+		if (big_oops_buf[pos]) {
 			zipped_len = pstore_compress(dst, psinfo->buf,
 						header_size + dump_size,
 						psinfo->bufsize);
@@ -372,6 +373,19 @@  static void pstore_dump(struct kmsg_dumper *dumper,
 	}
 }
 
+static void pstore_dump(struct kmsg_dumper *dumper,
+			enum kmsg_dump_reason reason)
+{
+	struct pstore_info_list *entry;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &psback->list_entry, list)
+		if (entry->psi->flags & PSTORE_FLAGS_DMESG)
+			pstore_do_dump(dumper, reason,
+				       entry->psi, entry->index);
+	rcu_read_unlock();
+}
+
 static struct kmsg_dumper pstore_dumper = {
 	.dump = pstore_dump,
 };
@@ -390,13 +404,11 @@  static void pstore_unregister_kmsg(void)
 }
 
 #ifdef CONFIG_PSTORE_CONSOLE
-static void pstore_console_write(struct console *con, const char *s, unsigned c)
+static void pstore_console_do_write(struct console *con, const char *s,
+				    unsigned c, struct pstore_info *psinfo)
 {
 	struct pstore_record record;
 
-	if (!c)
-		return;
-
 	pstore_record_init(&record, psinfo);
 	record.type = PSTORE_TYPE_CONSOLE;
 
@@ -405,6 +417,21 @@  static void pstore_console_write(struct console *con, const char *s, unsigned c)
 	psinfo->write(&record);
 }
 
+static void pstore_console_write(struct console *con, const char *s,
+				 unsigned int c)
+{
+	struct pstore_info_list *entry;
+
+	if (!c)
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &psback->list_entry, list)
+		if (entry->psi->flags & PSTORE_FLAGS_CONSOLE)
+			pstore_console_do_write(con, s, c, entry->psi);
+	rcu_read_unlock();
+}
+
 static struct console pstore_console = {
 	.write	= pstore_console_write,
 	.index	= -1,
@@ -413,7 +440,7 @@  static struct console pstore_console = {
 static void pstore_register_console(void)
 {
 	/* Show which backend is going to get console writes. */
-	strscpy(pstore_console.name, psinfo->name,
+	strscpy(pstore_console.name, "pstore console",
 		sizeof(pstore_console.name));
 	/*
 	 * Always initialize flags here since prior unregister_console()
@@ -464,12 +491,15 @@  static int pstore_write_user_compat(struct pstore_record *record,
  */
 int pstore_register(struct pstore_info *psi)
 {
+	struct pstore_info_list *entry;
+	struct pstore_info_list *newpsi;
 	char *new_backend;
 
-	if (backend && strcmp(backend, psi->name)) {
-		pr_warn("backend '%s' already in use: ignoring '%s'\n",
-			backend, psi->name);
-		return -EBUSY;
+	/* backend has to be enabled for going on registering */
+	if (backend && !strstr(backend, psi->name) &&
+	    strcmp(backend, "all")) {
+		pr_warn("backend '%s' not enabled\n", psi->name);
+		return -EINVAL;
 	}
 
 	/* Sanity check flags. */
@@ -486,79 +516,118 @@  int pstore_register(struct pstore_info *psi)
 		return -EINVAL;
 	}
 
-	new_backend = kstrdup(psi->name, GFP_KERNEL);
-	if (!new_backend)
-		return -ENOMEM;
-
-	mutex_lock(&psinfo_lock);
-	if (psinfo) {
-		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
-			psinfo->name, psi->name);
-		mutex_unlock(&psinfo_lock);
-		kfree(new_backend);
-		return -EBUSY;
+	mutex_lock(&psback_lock);
+
+	/*
+	 * If no backend specified, first come first served to
+	 * maintain backward compatibility
+	 */
+	if (!backend) {
+		pr_warn("no backend enabled, registering backend '%s'\n",
+			psi->name);
+		new_backend = kstrdup(psi->name, GFP_KERNEL);
+		if (!new_backend) {
+			mutex_unlock(&psback_lock);
+			return -ENOMEM;
+		}
+	}
+
+	if (psback) {
+		if (psback->flag == PSTORE_LIST_FULL) {
+			pr_warn("backend registration space is used up: "
+				"ignoring '%s'\n", psi->name);
+			mutex_unlock(&psback_lock);
+			return -EBUSY;
+		}
+		list_for_each_entry(entry, &psback->list_entry, list) {
+			if (strcmp(entry->psi->name, psi->name) == 0) {
+				pr_warn("backend '%s' already loaded\n",
+					psi->name);
+				mutex_unlock(&psback_lock);
+				return -EPERM;
+			}
+		}
+	} else {
+		psback = kzalloc(sizeof(*psback), GFP_KERNEL);
+		INIT_LIST_HEAD(&psback->list_entry);
 	}
 
 	if (!psi->write_user)
 		psi->write_user = pstore_write_user_compat;
-	psinfo = psi;
-	mutex_init(&psinfo->read_mutex);
-	spin_lock_init(&psinfo->buf_lock);
+	newpsi = kzalloc(sizeof(*newpsi), GFP_KERNEL);
+	newpsi->psi = psi;
+	newpsi->index = ffz(psback->flag);
+	psback->flag |= (1 << newpsi->index);
+
+	mutex_init(&psi->read_mutex);
+	spin_lock_init(&psi->buf_lock);
+
+	if (psi->flags & PSTORE_FLAGS_DMESG &&
+	    !psback->front_cnt[PSTORE_TYPE_DMESG])
+		allocate_buf_for_compression(psi, newpsi->index);
 
-	if (psi->flags & PSTORE_FLAGS_DMESG)
-		allocate_buf_for_compression();
+	pstore_get_records(psi, 0);
 
-	pstore_get_records(0);
+	list_add_rcu(&newpsi->list, &psback->list_entry);
 
-	if (psi->flags & PSTORE_FLAGS_DMESG) {
-		pstore_dumper.max_reason = psinfo->max_reason;
+	if (psi->flags & PSTORE_FLAGS_DMESG &&
+	    !psback->front_cnt[PSTORE_TYPE_DMESG]++) {
+		pstore_dumper.max_reason = psi->max_reason;
 		pstore_register_kmsg();
 	}
-	if (psi->flags & PSTORE_FLAGS_CONSOLE)
+	if (psi->flags & PSTORE_FLAGS_CONSOLE
+	    && !psback->front_cnt[PSTORE_TYPE_CONSOLE]++)
 		pstore_register_console();
-	if (psi->flags & PSTORE_FLAGS_FTRACE)
+	if (psi->flags & PSTORE_FLAGS_FTRACE &&
+	    !psback->front_cnt[PSTORE_TYPE_FTRACE]++)
 		pstore_register_ftrace();
-	if (psi->flags & PSTORE_FLAGS_PMSG)
+	if (psi->flags & PSTORE_FLAGS_PMSG &&
+	    !psback->front_cnt[PSTORE_TYPE_PMSG]++)
 		pstore_register_pmsg();
 
 	/* Start watching for new records, if desired. */
 	pstore_timer_kick();
 
 	/*
-	 * Update the module parameter backend, so it is visible
+	 * When module parameter backend is not specified,
+	 * update the module parameter backend, so it is visible
 	 * through /sys/module/pstore/parameters/backend
 	 */
-	backend = new_backend;
+	if (!backend)
+		backend = new_backend;
 
 	pr_info("Registered %s as persistent store backend\n", psi->name);
 
-	mutex_unlock(&psinfo_lock);
+	mutex_unlock(&psback_lock);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_register);
 
 void pstore_unregister(struct pstore_info *psi)
 {
+	struct pstore_info_list *entry;
 	/* It's okay to unregister nothing. */
 	if (!psi)
 		return;
 
-	mutex_lock(&psinfo_lock);
-
-	/* Only one backend can be registered at a time. */
-	if (WARN_ON(psi != psinfo)) {
-		mutex_unlock(&psinfo_lock);
+	/* Can not unregister an unenabled backend*/
+	if (WARN_ON(!strstr(backend, psi->name) && strcmp(backend, "all")))
 		return;
-	}
+
+	mutex_lock(&psback_lock);
 
 	/* Unregister all callbacks. */
-	if (psi->flags & PSTORE_FLAGS_PMSG)
+	if (psi->flags & PSTORE_FLAGS_PMSG &&
+	    !--psback->front_cnt[PSTORE_TYPE_PMSG])
 		pstore_unregister_pmsg();
-	if (psi->flags & PSTORE_FLAGS_FTRACE)
+	if (psi->flags & PSTORE_FLAGS_FTRACE &&
+	    !--psback->front_cnt[PSTORE_TYPE_FTRACE])
 		pstore_unregister_ftrace();
-	if (psi->flags & PSTORE_FLAGS_CONSOLE)
+	if (psi->flags & PSTORE_FLAGS_CONSOLE &&
+	    !--psback->front_cnt[PSTORE_TYPE_CONSOLE])
 		pstore_unregister_console();
-	if (psi->flags & PSTORE_FLAGS_DMESG)
+	if (psi->flags & PSTORE_FLAGS_DMESG &&
+	    !--psback->front_cnt[PSTORE_TYPE_DMESG])
 		pstore_unregister_kmsg();
 
 	/* Stop timer and make sure all work has finished. */
@@ -568,19 +637,30 @@  void pstore_unregister(struct pstore_info *psi)
 	/* Remove all backend records from filesystem tree. */
 	pstore_put_backend_records(psi);
 
-	free_buf_for_compression();
+	list_for_each_entry(entry, &psback->list_entry, list) {
+		if (entry->psi == psi) {
+			list_del_rcu(&entry->list);
+			psback->flag ^= 1 << entry->index;
+			synchronize_rcu();
+			free_buf_for_compression(entry->index);
+			kfree(entry);
+			break;
+		}
+	}
 
-	psinfo = NULL;
-	kfree(backend);
-	backend = NULL;
+	if (psback->flag == PSOTRE_LIST_EMPTY) {
+		kfree(psback);
+		psback = NULL;
+	}
 
 	pr_info("Unregistered %s as persistent store backend\n", psi->name);
-	mutex_unlock(&psinfo_lock);
+	mutex_unlock(&psback_lock);
 }
 EXPORT_SYMBOL_GPL(pstore_unregister);
 
 static void decompress_record(struct pstore_record *record,
-			      struct z_stream_s *zstream)
+			      struct z_stream_s *zstream,
+			      struct pstore_info *psinfo)
 {
 	int ret;
 	int unzipped_len;
@@ -697,7 +777,7 @@  void pstore_get_backend_records(struct pstore_info *psi,
 			break;
 		}
 
-		decompress_record(record, &zstream);
+		decompress_record(record, &zstream, psi);
 		rc = pstore_mkfile(root, record);
 		if (rc) {
 			/* pstore_mkfile() did not take record, so free it. */
@@ -729,7 +809,12 @@  void pstore_get_backend_records(struct pstore_info *psi,
 
 static void pstore_dowork(struct work_struct *work)
 {
-	pstore_get_records(1);
+	struct pstore_info_list *entry;
+
+	mutex_lock(&psback_lock);
+	list_for_each_entry(entry, &psback->list_entry, list)
+		pstore_get_records(entry->psi, 1);
+	mutex_unlock(&psback_lock);
 }
 
 static void pstore_timefunc(struct timer_list *unused)
@@ -745,11 +830,15 @@  static void pstore_timefunc(struct timer_list *unused)
 static int __init pstore_init(void)
 {
 	int ret;
+	struct pstore_info_list *entry;
 
 	ret = pstore_init_fs();
-	if (ret)
-		free_buf_for_compression();
-
+	if (ret) {
+		mutex_lock(&psback_lock);
+		list_for_each_entry(entry, &psback->list_entry, list)
+			free_buf_for_compression(entry->index);
+		mutex_unlock(&psback_lock);
+	}
 	return ret;
 }
 late_initcall(pstore_init);
diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c
index 55f139afa327..9d5b8602e273 100644
--- a/fs/pstore/pmsg.c
+++ b/fs/pstore/pmsg.c
@@ -11,8 +11,9 @@ 
 
 static DEFINE_MUTEX(pmsg_lock);
 
-static ssize_t write_pmsg(struct file *file, const char __user *buf,
-			  size_t count, loff_t *ppos)
+static ssize_t do_write_pmsg(struct file *file, const char __user *buf,
+			     size_t count, loff_t *ppos,
+			     struct pstore_info *psinfo)
 {
 	struct pstore_record record;
 	int ret;
@@ -34,6 +35,25 @@  static ssize_t write_pmsg(struct file *file, const char __user *buf,
 	return ret ? ret : count;
 }
 
+static ssize_t write_pmsg(struct file *file, const char __user *buf,
+			  size_t count, loff_t *ppos)
+{
+	int ret, _ret;
+	struct pstore_info_list *entry;
+
+	mutex_lock(&psback_lock);
+	list_for_each_entry(entry, &psback->list_entry, list) {
+		if (entry->psi->flags & PSTORE_FLAGS_PMSG) {
+			_ret = do_write_pmsg(file, buf, count,
+					     ppos, entry->psi);
+			ret = ret > _ret ? ret : _ret;
+		}
+	}
+	mutex_unlock(&psback_lock);
+
+	return ret;
+}
+
 static const struct file_operations pmsg_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= noop_llseek,
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 638507a3c8ff..0d2be20c8929 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -201,6 +201,35 @@  struct pstore_info {
 	int		(*erase)(struct pstore_record *record);
 };
 
+/* Supported multibackends */
+#define PSTORE_MAX_BACKEND_LENGTH 100
+#define PSTORE_BACKEND_NUM 16
+
+#define PSTORE_LIST_FULL (BIT(PSTORE_BACKEND_NUM) - 1)
+#define PSOTRE_LIST_EMPTY 0
+
+extern struct mutex psback_lock;
+
+struct pstore_info_list {
+	struct pstore_info *psi;
+	struct list_head list;
+	int index;
+};
+
+/**
+ * struct pstore_backends - management of pstore backends
+ * @list_entry:	entry of pstore backend driver information list
+ * @front_cnt:	count of each enabled frontend
+ * @flag:	bitmap of enabled pstore backend
+ *
+ */
+
+struct pstore_backends {
+	struct list_head list_entry;
+	int front_cnt[PSTORE_TYPE_MAX];
+	u16 flag;
+};
+
 /* Supported frontends */
 #define PSTORE_FLAGS_DMESG	BIT(0)
 #define PSTORE_FLAGS_CONSOLE	BIT(1)