From 87836af1eafc6616bde680be556f49ba3325f798 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 11 Apr 2025 07:40:33 +0200 Subject: [PATCH] x86/alternatives: Add text_mutex) assert to smp_text_poke_batch_flush() It's possible to escape the text_mutex-held assert in smp_text_poke_batch_process() if the caller uses a properly batched and sorted series of patch requests, so add an explicit lockdep_assert_held() to make sure it's held by all callers. All text_poke_int3_*() APIs will call either smp_text_poke_batch_process() or smp_text_poke_batch_flush() internally. The text_mutex must be held, because tp_vec and tp_vec_nr et al are all globals, and the INT3 patching machinery itself relies on external serialization. Signed-off-by: Ingo Molnar Cc: Juergen Gross Cc: "H . Peter Anvin" Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250411054105.2341982-22-mingo@kernel.org --- arch/x86/kernel/alternative.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index b97abfb38c3b7..c53eb3b0454eb 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -2860,6 +2860,8 @@ static bool tp_order_fail(void *addr) static void smp_text_poke_batch_flush(void *addr) { + lockdep_assert_held(&text_mutex); + if (tp_vec_nr == TP_VEC_MAX || tp_order_fail(addr)) { smp_text_poke_batch_process(tp_vec, tp_vec_nr); tp_vec_nr = 0; -- 2.51.0