[GIT PULL] probes: fixes for v6.16

[GIT PULL] probes: fixes for v6.16

[Masami Hiramatsu]

Hi Linus,

Probes fixes for v6.16-rc6:

 - fprobe-event: The @params variable was being used in an error path
   without being initialized. The fix to return an error code.


Please pull the latest probes-fixes-v6.16-rc6 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
probes-fixes-v6.16-rc6

Tag SHA1: ce8ff29973d1200622606428e017c32f36535d8a
Head SHA1: 1ed171a3afe81531b3ace96bd151a372dda3ee25


Nathan Chancellor (1):
      tracing/probes: Avoid using params uninitialized in parse_btf_arg()

----
 kernel/trace/trace_probe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---------------------------
commit 1ed171a3afe81531b3ace96bd151a372dda3ee25
Author: Nathan Chancellor <nathan@kernel.org>
Date:   Tue Jul 15 20:19:44 2025 -0700

    tracing/probes: Avoid using params uninitialized in parse_btf_arg()
    
    After a recent change in clang to strengthen uninitialized warnings [1],
    it points out that in one of the error paths in parse_btf_arg(), params
    is used uninitialized:
    
      kernel/trace/trace_probe.c:660:19: warning: variable 'params' is uninitialized when used here [-Wuninitialized]
        660 |                         return PTR_ERR(params);
            |                                        ^~~~~~
    
    Match many other NO_BTF_ENTRY error cases and return -ENOENT, clearing
    up the warning.
    
    Link: https://lore.kernel.org/all/20250715-trace_probe-fix-const-uninit-warning-v1-1-98960f91dd04@kernel.org/
    
    Cc: stable@vger.kernel.org
    Closes: https://github.com/ClangBuiltLinux/linux/issues/2110
    Fixes: d157d7694460 ("tracing/probes: Support BTF field access from $retval")
    Link: https://github.com/llvm/llvm-project/commit/2464313eef01c5b1edf0eccf57a32cdee01472c7 [1]
    Signed-off-by: Nathan Chancellor <nathan@kernel.org>
    Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 424751cdf31f..40830a3ecd96 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -657,7 +657,7 @@ static int parse_btf_arg(char *varname,
 		ret = query_btf_context(ctx);
 		if (ret < 0 || ctx->nr_params == 0) {
 			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
-			return PTR_ERR(params);
+			return -ENOENT;
 		}
 	}
 	params = ctx->params;
-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [GIT PULL] probes: fixes for v6.16

[pr-tracker-bot]

The pull request you sent on Wed, 16 Jul 2025 15:22:01 +0900:

> git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git probes-fixes-v6.16-rc6

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/e2291551827fe5d2d3758c435c191d32b6d1350e

Thank you!

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[GIT PULL] probes: Fixes for v6.16

[Masami Hiramatsu]

Hi Linus,

Probes fixes for v6.16:

 - Fix a potential infinite recursion in fprobe by using preempt_*_notrace().


Please pull the latest probes-fixes-v6.16 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
probes-fixes-v6.16

Tag SHA1: 1d7c77d4dfae320b756b5d0bcd04ecce5a38fbeb
Head SHA1: a3e892ab0fc287389176eabdcd74234508f6e52d


Masami Hiramatsu (Google) (1):
      tracing: fprobe: Fix infinite recursion using preempt_*_notrace()

----
 kernel/trace/fprobe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---------------------------
commit a3e892ab0fc287389176eabdcd74234508f6e52d
Author: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date:   Tue Jul 29 08:47:03 2025 +0900

    tracing: fprobe: Fix infinite recursion using preempt_*_notrace()
    
    Since preempt_count_add/del() are tracable functions, it is not allowed
    to use preempt_disable/enable() in ftrace handlers. Without this fix,
    probing on `preempt_count_add%return` will cause an infinite recursion
    of fprobes.
    
    To fix this problem, use preempt_disable/enable_notrace() in
    fprobe_return().
    
    Link: https://lore.kernel.org/all/175374642359.1471729.1054175011228386560.stgit@mhiramat.tok.corp.google.com/
    
    Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer")
    Cc: stable@vger.kernel.org
    Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index ba7ff14f5339..f9b3aa9afb17 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -352,7 +352,7 @@ static void fprobe_return(struct ftrace_graph_ret *trace,
 	size_words = SIZE_IN_LONG(size);
 	ret_ip = ftrace_regs_get_instruction_pointer(fregs);
 
-	preempt_disable();
+	preempt_disable_notrace();
 
 	curr = 0;
 	while (size_words > curr) {
@@ -368,7 +368,7 @@ static void fprobe_return(struct ftrace_graph_ret *trace,
 		}
 		curr += size;
 	}
-	preempt_enable();
+	preempt_enable_notrace();
 }
 NOKPROBE_SYMBOL(fprobe_return);
 
-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [GIT PULL] probes: Fixes for v6.16

[pr-tracker-bot]

The pull request you sent on Tue, 29 Jul 2025 19:30:05 +0900:

> git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git probes-fixes-v6.16

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/a03eec74201251635dede6eb2c3f79c350863d7f

Thank you!

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