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authorDaniel Jordan <daniel.m.jordan@oracle.com>2022-11-16 20:28:02 -0500
committerHerbert Xu <herbert@gondor.apana.org.au>2022-11-25 17:39:18 +0800
commit34c3a47d20ae55b3600fed733bf96eafe9c500d5 (patch)
treeb561395c6d74757dcd6cef02edd3b3e8ca7e65f3 /kernel/padata.c
parent1aa33fc8d4032227253ceb736f47c52b859d9683 (diff)
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padata: Always leave BHs disabled when running ->parallel()
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>
Diffstat (limited to 'kernel/padata.c')
-rw-r--r--kernel/padata.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/padata.c b/kernel/padata.c
index e5819bb8bd1d..97f51e0c1776 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -207,14 +207,16 @@ 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;