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x86/alternatives: Add text_mutex) assert to smp_text_poke_batch_flush()

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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 <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-22-mingo@kernel.org
This commit is contained in:
Ingo Molnar 2025-04-11 07:40:33 +02:00
parent 3bd7546ff2
commit 87836af1ea
1 changed files with 2 additions and 0 deletions
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2
arch/x86/kernel/alternative.c
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@ -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;