From 53d472f97235346f77fc2c9305438b9d9a595229 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 4 Nov 2024 14:39:10 +0100 Subject: [PATCH] lockdep/mm: Fix might_fault() lockdep check of current->mm->mmap_lock [ Upstream commit a1b65f3f7c6f7f0a08a7dba8be458c6415236487 ] Turns out that this commit, about 10 years ago: 9ec23531fd48 ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults") ... accidentally (and unnessecarily) put the lockdep part of __might_fault() under CONFIG_DEBUG_ATOMIC_SLEEP=y. This is potentially notable because large distributions such as Ubuntu are running with !CONFIG_DEBUG_ATOMIC_SLEEP. Restore the debug check. [ mingo: Update changelog. ] Fixes: 9ec23531fd48 ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Linus Torvalds Cc: Andrew Morton Link: https://lore.kernel.org/r/20241104135517.536628371@infradead.org Signed-off-by: Sasha Levin --- mm/memory.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index fd874df17b36..2e776ea38348 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5848,10 +5848,8 @@ void __might_fault(const char *file, int line) if (pagefault_disabled()) return; __might_sleep(file, line); -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) if (current->mm) might_lock_read(¤t->mm->mmap_lock); -#endif } EXPORT_SYMBOL(__might_fault); #endif