[v2,4/6] panic: Consolidate open-coded panic_on_warn checks

Message ID 20221109200050.3400857-4-keescook@chromium.org
State New
Headers
Series exit: Put an upper limit on how often we can oops |

Commit Message

Kees Cook Nov. 9, 2022, 8 p.m. UTC
  Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll
their own warnings, and each check "panic_on_warn". Consolidate this
into a single function so that future instrumentation can be added in
a single location.

Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: David Gow <davidgow@google.com>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: Jann Horn <jannh@google.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/panic.h | 1 +
 kernel/kcsan/report.c | 3 +--
 kernel/panic.c        | 9 +++++++--
 kernel/sched/core.c   | 3 +--
 lib/ubsan.c           | 3 +--
 mm/kasan/report.c     | 4 ++--
 mm/kfence/report.c    | 3 +--
 7 files changed, 14 insertions(+), 12 deletions(-)
  

Comments

Marco Elver Nov. 14, 2022, 9:57 a.m. UTC | #1
On Wed, 9 Nov 2022 at 21:00, Kees Cook <keescook@chromium.org> wrote:
>
> Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll
> their own warnings, and each check "panic_on_warn". Consolidate this
> into a single function so that future instrumentation can be added in
> a single location.
>
> Cc: Marco Elver <elver@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ben Segall <bsegall@google.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: David Gow <davidgow@google.com>
> Cc: tangmeng <tangmeng@uniontech.com>
> Cc: Jann Horn <jannh@google.com>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
> Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> Cc: kasan-dev@googlegroups.com
> Cc: linux-mm@kvack.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  include/linux/panic.h | 1 +
>  kernel/kcsan/report.c | 3 +--
>  kernel/panic.c        | 9 +++++++--
>  kernel/sched/core.c   | 3 +--
>  lib/ubsan.c           | 3 +--
>  mm/kasan/report.c     | 4 ++--
>  mm/kfence/report.c    | 3 +--
>  7 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/panic.h b/include/linux/panic.h
> index c7759b3f2045..1702aeb74927 100644
> --- a/include/linux/panic.h
> +++ b/include/linux/panic.h
> @@ -11,6 +11,7 @@ extern long (*panic_blink)(int state);
>  __printf(1, 2)
>  void panic(const char *fmt, ...) __noreturn __cold;
>  void nmi_panic(struct pt_regs *regs, const char *msg);
> +void check_panic_on_warn(const char *reason);
>  extern void oops_enter(void);
>  extern void oops_exit(void);
>  extern bool oops_may_print(void);
> diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
> index 67794404042a..e95ce7d7a76e 100644
> --- a/kernel/kcsan/report.c
> +++ b/kernel/kcsan/report.c
> @@ -492,8 +492,7 @@ static void print_report(enum kcsan_value_change value_change,
>         dump_stack_print_info(KERN_DEFAULT);
>         pr_err("==================================================================\n");
>
> -       if (panic_on_warn)
> -               panic("panic_on_warn set ...\n");
> +       check_panic_on_warn("KCSAN");
>  }
>
>  static void release_report(unsigned long *flags, struct other_info *other_info)
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 129936511380..3afd234767bc 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -201,6 +201,12 @@ static void panic_print_sys_info(bool console_flush)
>                 ftrace_dump(DUMP_ALL);
>  }
>
> +void check_panic_on_warn(const char *reason)
> +{
> +       if (panic_on_warn)
> +               panic("%s: panic_on_warn set ...\n", reason);
> +}
> +
>  /**
>   *     panic - halt the system
>   *     @fmt: The text string to print
> @@ -619,8 +625,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
>         if (regs)
>                 show_regs(regs);
>
> -       if (panic_on_warn)
> -               panic("panic_on_warn set ...\n");
> +       check_panic_on_warn("kernel");

What is the reason "kernel" in this context? The real reason is a WARN
- so would the reason "WARNING" be more intuitive?
  
Kees Cook Nov. 17, 2022, 11:28 p.m. UTC | #2
On Mon, Nov 14, 2022 at 10:57:15AM +0100, Marco Elver wrote:
> On Wed, 9 Nov 2022 at 21:00, Kees Cook <keescook@chromium.org> wrote:
> >
> > Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll
> > their own warnings, and each check "panic_on_warn". Consolidate this
> > into a single function so that future instrumentation can be added in
> > a single location.
> >
> > Cc: Marco Elver <elver@google.com>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Juri Lelli <juri.lelli@redhat.com>
> > Cc: Vincent Guittot <vincent.guittot@linaro.org>
> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: Ben Segall <bsegall@google.com>
> > Cc: Mel Gorman <mgorman@suse.de>
> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
> > Cc: Valentin Schneider <vschneid@redhat.com>
> > Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> > Cc: Alexander Potapenko <glider@google.com>
> > Cc: Andrey Konovalov <andreyknvl@gmail.com>
> > Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Luis Chamberlain <mcgrof@kernel.org>
> > Cc: David Gow <davidgow@google.com>
> > Cc: tangmeng <tangmeng@uniontech.com>
> > Cc: Jann Horn <jannh@google.com>
> > Cc: Petr Mladek <pmladek@suse.com>
> > Cc: "Paul E. McKenney" <paulmck@kernel.org>
> > Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
> > Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> > Cc: kasan-dev@googlegroups.com
> > Cc: linux-mm@kvack.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  include/linux/panic.h | 1 +
> >  kernel/kcsan/report.c | 3 +--
> >  kernel/panic.c        | 9 +++++++--
> >  kernel/sched/core.c   | 3 +--
> >  lib/ubsan.c           | 3 +--
> >  mm/kasan/report.c     | 4 ++--
> >  mm/kfence/report.c    | 3 +--
> >  7 files changed, 14 insertions(+), 12 deletions(-)
> >
> > diff --git a/include/linux/panic.h b/include/linux/panic.h
> > index c7759b3f2045..1702aeb74927 100644
> > --- a/include/linux/panic.h
> > +++ b/include/linux/panic.h
> > @@ -11,6 +11,7 @@ extern long (*panic_blink)(int state);
> >  __printf(1, 2)
> >  void panic(const char *fmt, ...) __noreturn __cold;
> >  void nmi_panic(struct pt_regs *regs, const char *msg);
> > +void check_panic_on_warn(const char *reason);
> >  extern void oops_enter(void);
> >  extern void oops_exit(void);
> >  extern bool oops_may_print(void);
> > diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
> > index 67794404042a..e95ce7d7a76e 100644
> > --- a/kernel/kcsan/report.c
> > +++ b/kernel/kcsan/report.c
> > @@ -492,8 +492,7 @@ static void print_report(enum kcsan_value_change value_change,
> >         dump_stack_print_info(KERN_DEFAULT);
> >         pr_err("==================================================================\n");
> >
> > -       if (panic_on_warn)
> > -               panic("panic_on_warn set ...\n");
> > +       check_panic_on_warn("KCSAN");
> >  }
> >
> >  static void release_report(unsigned long *flags, struct other_info *other_info)
> > diff --git a/kernel/panic.c b/kernel/panic.c
> > index 129936511380..3afd234767bc 100644
> > --- a/kernel/panic.c
> > +++ b/kernel/panic.c
> > @@ -201,6 +201,12 @@ static void panic_print_sys_info(bool console_flush)
> >                 ftrace_dump(DUMP_ALL);
> >  }
> >
> > +void check_panic_on_warn(const char *reason)
> > +{
> > +       if (panic_on_warn)
> > +               panic("%s: panic_on_warn set ...\n", reason);
> > +}
> > +
> >  /**
> >   *     panic - halt the system
> >   *     @fmt: The text string to print
> > @@ -619,8 +625,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
> >         if (regs)
> >                 show_regs(regs);
> >
> > -       if (panic_on_warn)
> > -               panic("panic_on_warn set ...\n");
> > +       check_panic_on_warn("kernel");
> 
> What is the reason "kernel" in this context? The real reason is a WARN
> - so would the reason "WARNING" be more intuitive?

I'll rename "reason" to "origin" or something -- it's mainly to see
who was calling this when it's not core kernel logic.
  

Patch

diff --git a/include/linux/panic.h b/include/linux/panic.h
index c7759b3f2045..1702aeb74927 100644
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -11,6 +11,7 @@  extern long (*panic_blink)(int state);
 __printf(1, 2)
 void panic(const char *fmt, ...) __noreturn __cold;
 void nmi_panic(struct pt_regs *regs, const char *msg);
+void check_panic_on_warn(const char *reason);
 extern void oops_enter(void);
 extern void oops_exit(void);
 extern bool oops_may_print(void);
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
index 67794404042a..e95ce7d7a76e 100644
--- a/kernel/kcsan/report.c
+++ b/kernel/kcsan/report.c
@@ -492,8 +492,7 @@  static void print_report(enum kcsan_value_change value_change,
 	dump_stack_print_info(KERN_DEFAULT);
 	pr_err("==================================================================\n");
 
-	if (panic_on_warn)
-		panic("panic_on_warn set ...\n");
+	check_panic_on_warn("KCSAN");
 }
 
 static void release_report(unsigned long *flags, struct other_info *other_info)
diff --git a/kernel/panic.c b/kernel/panic.c
index 129936511380..3afd234767bc 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -201,6 +201,12 @@  static void panic_print_sys_info(bool console_flush)
 		ftrace_dump(DUMP_ALL);
 }
 
+void check_panic_on_warn(const char *reason)
+{
+	if (panic_on_warn)
+		panic("%s: panic_on_warn set ...\n", reason);
+}
+
 /**
  *	panic - halt the system
  *	@fmt: The text string to print
@@ -619,8 +625,7 @@  void __warn(const char *file, int line, void *caller, unsigned taint,
 	if (regs)
 		show_regs(regs);
 
-	if (panic_on_warn)
-		panic("panic_on_warn set ...\n");
+	check_panic_on_warn("kernel");
 
 	if (!regs)
 		dump_stack();
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5800b0623ff3..285ef8821b4f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5729,8 +5729,7 @@  static noinline void __schedule_bug(struct task_struct *prev)
 		pr_err("Preemption disabled at:");
 		print_ip_sym(KERN_ERR, preempt_disable_ip);
 	}
-	if (panic_on_warn)
-		panic("scheduling while atomic\n");
+	check_panic_on_warn("scheduling while atomic");
 
 	dump_stack();
 	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
diff --git a/lib/ubsan.c b/lib/ubsan.c
index 36bd75e33426..60c7099857a0 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -154,8 +154,7 @@  static void ubsan_epilogue(void)
 
 	current->in_ubsan--;
 
-	if (panic_on_warn)
-		panic("panic_on_warn set ...\n");
+	check_panic_on_warn("UBSAN");
 }
 
 void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index df3602062bfd..cc98dfdd3ed2 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -164,8 +164,8 @@  static void end_report(unsigned long *flags, void *addr)
 				       (unsigned long)addr);
 	pr_err("==================================================================\n");
 	spin_unlock_irqrestore(&report_lock, *flags);
-	if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
-		panic("panic_on_warn set ...\n");
+	if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
+		check_panic_on_warn("KASAN");
 	if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC)
 		panic("kasan.fault=panic set ...\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index 7e496856c2eb..110c27ca597d 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -268,8 +268,7 @@  void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 
 	lockdep_on();
 
-	if (panic_on_warn)
-		panic("panic_on_warn set ...\n");
+	check_panic_on_warn("KFENCE");
 
 	/* We encountered a memory safety error, taint the kernel! */
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);