6.6-stable review patch. If anyone has any objections, please let me know.
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From: Josh Poimboeuf jpoimboe@kernel.org
[ Upstream commit 153f9e74dec230f2e070e16fa061bc7adfd2c450 ]
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 Signed-off-by: Sasha Levin sashal@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 65fea424874c5..ee01cfcc35064 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -184,6 +184,10 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, struct perf_callchain_entry_ctx ctx; int rctx;
+ /* crosstask is not supported for user stacks */ + if (crosstask && user && !kernel) + return NULL; + entry = get_callchain_entry(&rctx); if (!entry) return NULL; @@ -200,7 +204,7 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, perf_callchain_kernel(&ctx, regs); }
- if (user) { + if (user && !crosstask) { if (!user_mode(regs)) { if (current->flags & (PF_KTHREAD | PF_USER_WORKER)) regs = NULL; @@ -209,9 +213,6 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, }
if (regs) { - if (crosstask) - goto exit_put; - if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
@@ -219,7 +220,6 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, } }
-exit_put: put_callchain_entry(rctx);
return entry;