[PATCH] kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

syzbot is reporting lockdep warning in __stack_depot_save(), for
the caller of __stack_depot_save() (i.e. __kasan_record_aux_stack() in
this report) is responsible for masking __GFP_KSWAPD_RECLAIM flag in
order not to wake kswapd which in turn wakes kcompactd.

Since kasan/kmsan functions might be called with arbitrary locks held,
mask __GFP_KSWAPD_RECLAIM flag from all GFP_NOWAIT/GFP_ATOMIC allocations
in kasan/kmsan.

Note that kmsan_save_stack_with_flags() is changed to mask both
__GFP_DIRECT_RECLAIM flag and __GFP_KSWAPD_RECLAIM flag, for
wakeup_kswapd() from wake_all_kswapds() from __alloc_pages_slowpath()
calls wakeup_kcompactd() if __GFP_KSWAPD_RECLAIM flag is set and
__GFP_DIRECT_RECLAIM flag is not set.

Reported-by: syzbot <syzbot+ece2915262061d6e0ac1@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=ece2915262061d6e0ac1
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 mm/kasan/generic.c         | 4 ++--
 mm/kasan/tags.c            | 2 +-
 mm/kmsan/core.c            | 6 +++---
 mm/kmsan/instrumentation.c | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index e5eef670735e..2c94f4943240 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -488,7 +488,7 @@ static void __kasan_record_aux_stack(void *addr, bool can_alloc)
 		return;
 
 	alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
-	alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT, can_alloc);
+	alloc_meta->aux_stack[0] = kasan_save_stack(0, can_alloc);
 }
 
 void kasan_record_aux_stack(void *addr)
@@ -518,7 +518,7 @@ void kasan_save_free_info(struct kmem_cache *cache, void *object)
 	if (!free_meta)
 		return;
 
-	kasan_set_track(&free_meta->free_track, GFP_NOWAIT);
+	kasan_set_track(&free_meta->free_track, 0);
 	/* The object was freed and has free track set. */
 	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK;
 }
diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
index 67a222586846..7dcfe341d48e 100644
--- a/mm/kasan/tags.c
+++ b/mm/kasan/tags.c
@@ -140,5 +140,5 @@ void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
 
 void kasan_save_free_info(struct kmem_cache *cache, void *object)
 {
-	save_stack_info(cache, object, GFP_NOWAIT, true);
+	save_stack_info(cache, object, 0, true);
 }
diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c
index 7d1e4aa30bae..3adb4c1d3b19 100644
--- a/mm/kmsan/core.c
+++ b/mm/kmsan/core.c
@@ -74,7 +74,7 @@ depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags,
 	nr_entries = stack_trace_save(entries, KMSAN_STACK_DEPTH, 0);
 
 	/* Don't sleep. */
-	flags &= ~__GFP_DIRECT_RECLAIM;
+	flags &= ~(__GFP_DIRECT_RECLAIM | __GFP_KSWAPD_RECLAIM);
 
 	handle = __stack_depot_save(entries, nr_entries, flags, true);
 	return stack_depot_set_extra_bits(handle, extra);
@@ -245,7 +245,7 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id)
 	extra_bits = kmsan_extra_bits(depth, uaf);
 
 	entries[0] = KMSAN_CHAIN_MAGIC_ORIGIN;
-	entries[1] = kmsan_save_stack_with_flags(GFP_ATOMIC, 0);
+	entries[1] = kmsan_save_stack_with_flags(__GFP_HIGH, 0);
 	entries[2] = id;
 	/*
 	 * @entries is a local var in non-instrumented code, so KMSAN does not
@@ -253,7 +253,7 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id)
 	 * positives when __stack_depot_save() passes it to instrumented code.
 	 */
 	kmsan_internal_unpoison_memory(entries, sizeof(entries), false);
-	handle = __stack_depot_save(entries, ARRAY_SIZE(entries), GFP_ATOMIC,
+	handle = __stack_depot_save(entries, ARRAY_SIZE(entries), __GFP_HIGH,
 				    true);
 	return stack_depot_set_extra_bits(handle, extra_bits);
 }
diff --git a/mm/kmsan/instrumentation.c b/mm/kmsan/instrumentation.c
index cf12e9616b24..cc3907a9c33a 100644
--- a/mm/kmsan/instrumentation.c
+++ b/mm/kmsan/instrumentation.c
@@ -282,7 +282,7 @@ void __msan_poison_alloca(void *address, uintptr_t size, char *descr)
 
 	/* stack_depot_save() may allocate memory. */
 	kmsan_enter_runtime();
-	handle = stack_depot_save(entries, ARRAY_SIZE(entries), GFP_ATOMIC);
+	handle = stack_depot_save(entries, ARRAY_SIZE(entries), __GFP_HIGH);
 	kmsan_leave_runtime();
 
 	kmsan_internal_set_shadow_origin(address, size, -1, handle,
-- 
2.34.1