diff options
| author | Daniel Jordan <daniel.m.jordan@oracle.com> | 2022-11-16 20:28:02 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-14 10:15:50 +0100 |
| commit | 8e0681dd4eee029eb1d533d06993f7cb091efb73 (patch) | |
| tree | debebbe263a5abcfb84259e52bff869c5485a1c6 /kernel | |
| parent | 4a99e6a1049cad270a9c7a8608d063f9f1df1abf (diff) | |
padata: Always leave BHs disabled when running ->parallel()
[ Upstream commit 34c3a47d20ae55b3600fed733bf96eafe9c500d5 ]
A deadlock can happen when an overloaded system runs ->parallel() in the
context of the current task:
padata_do_parallel
->parallel()
pcrypt_aead_enc/dec
padata_do_serial
spin_lock(&reorder->lock) // BHs still enabled
<interrupt>
...
__do_softirq
...
padata_do_serial
spin_lock(&reorder->lock)
It's a bug for BHs to be on in _do_serial as Steffen points out, so
ensure they're off in the "current task" case like they are in
padata_parallel_worker to avoid this situation.
Reported-by: syzbot+bc05445bc14148d51915@syzkaller.appspotmail.com
Fixes: 4611ce224688 ("padata: allocate work structures for parallel jobs from a pool")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/padata.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/padata.c b/kernel/padata.c index d4d3ba6e1728..4d31a69a9b38 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -220,14 +220,16 @@ int padata_do_parallel(struct padata_shell *ps, pw = padata_work_alloc(); spin_unlock(&padata_works_lock); + if (!pw) { + /* Maximum works limit exceeded, run in the current task. */ + padata->parallel(padata); + } + rcu_read_unlock_bh(); if (pw) { padata_work_init(pw, padata_parallel_worker, padata, 0); queue_work(pinst->parallel_wq, &pw->pw_work); - } else { - /* Maximum works limit exceeded, run in the current task. */ - padata->parallel(padata); } return 0; |