[PATCH v6 12/18] perf: Simplify get_perf_callchain() user logic
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2025-04-25 14:56:15
Also in:
linux-perf-users, linux-toolchains, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: Josh Poimboeuf <jpoimboe@kernel.org> Simplify the get_perf_callchain() user logic a bit. task_pt_regs() should never be NULL. Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- Changes since v5: https://lore.kernel.org/20250424162633.048002581@goodmis.org (local) - Use (current->flags & PF_KTHREAD) instead of current->mm == NULL to determine if a task is a kernel thread or not (Peter Zijlstra) kernel/events/callchain.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index cda145dc11bd..2798c0c9f782 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c@@ -247,21 +247,19 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, if (user) { if (!user_mode(regs)) { if (current->flags & PF_KTHREAD) - regs = NULL; - else - regs = task_pt_regs(current); + goto exit_put; + regs = task_pt_regs(current); } - if (regs) { - if (add_mark) - perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); + if (add_mark) + perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); - start_entry_idx = entry->nr; - perf_callchain_user(&ctx, regs); - fixup_uretprobe_trampoline_entries(entry, start_entry_idx); - } + start_entry_idx = entry->nr; + perf_callchain_user(&ctx, regs); + fixup_uretprobe_trampoline_entries(entry, start_entry_idx); } +exit_put: put_callchain_entry(rctx); return entry;
--
2.47.2