The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 11aff32439df6ca5b3b891b43032faf88f4a6a29 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025051938-tweezers-vendor-8ef7@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 11aff32439df6ca5b3b891b43032faf88f4a6a29 Mon Sep 17 00:00:00 2001 From: pengdonglin pengdonglin@xiaomi.com Date: Mon, 12 May 2025 17:42:46 +0800 Subject: [PATCH] ftrace: Fix preemption accounting for stacktrace filter command
The preemption count of the stacktrace filter command to trace ksys_read is consistently incorrect:
$ echo ksys_read:stacktrace > set_ftrace_filter
<...>-453 [004] ...1. 38.308956: <stack trace> => ksys_read => do_syscall_64 => entry_SYSCALL_64_after_hwframe
The root cause is that the trace framework disables preemption when invoking the filter command callback in function_trace_probe_call:
preempt_disable_notrace(); probe_ops->func(ip, parent_ip, probe_opsbe->tr, probe_ops, probe->data); preempt_enable_notrace();
Use tracing_gen_ctx_dec() to account for the preempt_disable_notrace(), which will output the correct preemption count:
$ echo ksys_read:stacktrace > set_ftrace_filter
<...>-410 [006] ..... 31.420396: <stack trace> => ksys_read => do_syscall_64 => entry_SYSCALL_64_after_hwframe
Cc: stable@vger.kernel.org Fixes: 36590c50b2d07 ("tracing: Merge irqflags + preempt counter.") Link: https://lore.kernel.org/20250512094246.1167956-2-dolinux.peng@gmail.com Signed-off-by: pengdonglin dolinux.peng@gmail.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 98ccf3f00c51..4e37a0f6aaa3 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -633,11 +633,7 @@ ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
static __always_inline void trace_stack(struct trace_array *tr) { - unsigned int trace_ctx; - - trace_ctx = tracing_gen_ctx(); - - __trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP); + __trace_stack(tr, tracing_gen_ctx_dec(), FTRACE_STACK_SKIP); }
static void