The following commit has been merged into the perf/core branch of tip:
Commit-ID: 153f9e74dec230f2e070e16fa061bc7adfd2c450
Gitweb: https://git.kernel.org/tip/153f9e74dec230f2e070e16fa061bc7adfd2c450
Author: Josh Poimboeuf <jpoimboe@kernel.org>
AuthorDate: Wed, 20 Aug 2025 14:03:40 -04:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 26 Aug 2025 09:51:12 +02:00
perf: Have get_perf_callchain() return NULL if crosstask and user are set
get_perf_callchain() doesn't support cross-task unwinding for user space
stacks, have it return NULL if both the crosstask and user arguments are
set.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250820180428.426423415@kernel.org
---
kernel/events/callchain.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index b0f5bd2..cd0e3fc 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -224,6 +224,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
struct perf_callchain_entry_ctx ctx;
int rctx, start_entry_idx;
+ /* crosstask is not supported for user stacks */
+ if (crosstask && user && !kernel)
+ return NULL;
+
entry = get_callchain_entry(&rctx);
if (!entry)
return NULL;
@@ -240,7 +244,7 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
perf_callchain_kernel(&ctx, regs);
}
- if (user) {
+ if (user && !crosstask) {
if (!user_mode(regs)) {
if (current->mm)
regs = task_pt_regs(current);
@@ -249,9 +253,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
}
if (regs) {
- if (crosstask)
- goto exit_put;
-
if (add_mark)
perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
@@ -261,7 +262,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
}
}
-exit_put:
put_callchain_entry(rctx);
return entry;