diff mbox series

[for-next,03/12] tracing: Have the user copy of synthetic event address use correct context

Message ID 20231101213802.233842141@goodmis.org
State New
Headers
Series tracing: Final (hopefully!) updates for v6.7 |

Commit Message

Steven Rostedt Nov. 1, 2023, 9:37 p.m. UTC 
  From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

A synthetic event is created by the synthetic event interface that can
read both user or kernel address memory. In reality, it reads any
arbitrary memory location from within the kernel. If the address space is
in USER (where CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE is set) then
it uses strncpy_from_user_nofault() to copy strings otherwise it uses
strncpy_from_kernel_nofault().

But since both functions use the same variable there's no annotation to
what that variable is (ie. __user). This makes sparse complain.

Quiet sparse by typecasting the strncpy_from_user_nofault() variable to
a __user pointer.

Link: https://lore.kernel.org/linux-trace-kernel/20231031151033.73c42e23@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 0934ae9977c2 ("tracing: Fix reading strings from synthetic events");
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311010013.fm8WTxa5-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_synth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 14cb275a0bab..846e02c0fb59 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -452,7 +452,7 @@  static unsigned int trace_string(struct synth_trace_event *entry,
 
 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 		if ((unsigned long)str_val < TASK_SIZE)
-			ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
+			ret = strncpy_from_user_nofault(str_field, (const void __user *)str_val, STR_VAR_LEN_MAX);
 		else
 #endif
 			ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);