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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2023-05-11 22:47:32 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-30 13:55:31 +0100 |
| commit | aee97eec77029270866c704f66cdf2881cbd2fe1 (patch) | |
| tree | 6bc7de755c997641256a267c8d77d1b66189c136 | |
| parent | c09a7b6190f5a5d8324c84b8e88f02e9861af735 (diff) | |
| download | linux-aee97eec77029270866c704f66cdf2881cbd2fe1.tar.gz linux-aee97eec77029270866c704f66cdf2881cbd2fe1.tar.bz2 linux-aee97eec77029270866c704f66cdf2881cbd2fe1.zip | |
debugobjects: Don't wake up kswapd from fill_pool()
commit eb799279fb1f9c63c520fe8c1c41cb9154252db6 upstream.
syzbot is reporting a lockdep warning in fill_pool() because the allocation
from debugobjects is using GFP_ATOMIC, which is (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)
and therefore tries to wake up kswapd, which acquires kswapd_wait::lock.
Since fill_pool() might be called with arbitrary locks held, fill_pool()
should not assume that acquiring kswapd_wait::lock is safe.
Use __GFP_HIGH instead and remove __GFP_NORETRY as it is pointless for
!__GFP_DIRECT_RECLAIM allocation.
Fixes: 3ac7fe5a4aab ("infrastructure to debug (dynamic) objects")
Reported-by: syzbot <syzbot+fe0c72f0ccbb93786380@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/6577e1fa-b6ee-f2be-2414-a2b51b1c5e30@I-love.SAKURA.ne.jp
Closes: https://syzkaller.appspot.com/bug?extid=fe0c72f0ccbb93786380
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | lib/debugobjects.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 824337ec36aa..4c39678c03ee 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -129,7 +129,7 @@ static const char *obj_states[ODEBUG_STATE_MAX] = { static void fill_pool(void) { - gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN; + gfp_t gfp = __GFP_HIGH | __GFP_NOWARN; struct debug_obj *obj; unsigned long flags; |