[PATCH v10 03/11] perf: Use current->flags & PF_KTHREAD instead of current->mm == NULL
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2025-06-14 02:46:11
Also in:
bpf, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: Steven Rostedt <rostedt@goodmis.org> To determine if a task is a kernel thread or not, it is more reliable to use (current->flags & PF_KTHREAD) than to rely on current->mm being NULL. That is because some kernel tasks (io_uring helpers) may have a mm field. Link: https://lore.kernel.org/linux-trace-kernel/20250424163607.GE18306@noisy.programming.kicks-ass.net/ (local) Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- kernel/events/callchain.c | 6 +++--- kernel/events/core.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index cd0e3fc7ed05..42d21761cb4d 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c@@ -246,10 +246,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, if (user && !crosstask) { if (!user_mode(regs)) { - if (current->mm) - regs = task_pt_regs(current); - else + if (current->flags & PF_KTHREAD) regs = NULL; + else + regs = task_pt_regs(current); } if (regs) {
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d8688668d21a..375115492c02 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c@@ -8032,7 +8032,7 @@ static u64 perf_virt_to_phys(u64 virt) * Try IRQ-safe get_user_page_fast_only first. * If failed, leave phys_addr as 0. */ - if (current->mm != NULL) { + if (!(current->flags & PF_KTHREAD)) { struct page *p; pagefault_disable();
--
2.47.2