From: levi.yun <yeoreum.yun@xxxxxxx> commit 7dc836187f7c6f70a82b4521503e9f9f96194581 upstream. pid_list_fill_irq() runs via irq_work. When CONFIG_PREEMPT_RT is disabled, it would run in irq_context. so it shouldn't sleep while memory allocation. Change gfp flags from GFP_KERNEL to GFP_NOWAIT to prevent sleep in irq_work. This change wouldn't impact functionality in practice because the worst-size is 2K. Cc: stable@xxxxxxxxxxx Fixes: 8d6e90983ade2 ("tracing: Create a sparse bitmask for pid filtering") Link: https://lore.kernel.org/20240704150226.1359936-1-yeoreum.yun@xxxxxxx Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Signed-off-by: levi.yun <yeoreum.yun@xxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/pid_list.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/trace/pid_list.c +++ b/kernel/trace/pid_list.c @@ -354,7 +354,7 @@ static void pid_list_refill_irq(struct i while (upper_count-- > 0) { union upper_chunk *chunk; - chunk = kzalloc(sizeof(*chunk), GFP_KERNEL); + chunk = kzalloc(sizeof(*chunk), GFP_NOWAIT); if (!chunk) break; *upper_next = chunk; @@ -365,7 +365,7 @@ static void pid_list_refill_irq(struct i while (lower_count-- > 0) { union lower_chunk *chunk; - chunk = kzalloc(sizeof(*chunk), GFP_KERNEL); + chunk = kzalloc(sizeof(*chunk), GFP_NOWAIT); if (!chunk) break; *lower_next = chunk; Patches currently in stable-queue which might be from yeoreum.yun@xxxxxxx are queue-6.1/trace-pid_list-change-gfp-flags-in-pid_list_fill_irq.patch