[PATCH AUTOSEL 6.1 2/9] padata: Disable BH when taking works lock on MT path

Sasha Levin
2024-05-26T09:43:16Z

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit 58329c4312031603bb1786b44265c26d5065fe72 ]

As the old padata code can execute in softirq context, disable
softirqs for the new padata_do_mutithreaded code too as otherwise
lockdep will get antsy.

Reported-by: syzbot+0cb5bb0f4bf9e79db3b3@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/padata.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 7bef7dae3db54..0261bced7eb6e 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -98,7 +98,7 @@ static int __init padata_work_alloc_mt(int nworks, void *data,
{
int i;

- spin_lock(&padata_works_lock);
+ spin_lock_bh(&padata_works_lock);
/* Start at 1 because the current task participates in the job. */
for (i = 1; i < nworks; ++i) {
struct padata_work *pw = padata_work_alloc();
@@ -108,7 +108,7 @@ static int __init padata_work_alloc_mt(int nworks, void *data,
padata_work_init(pw, padata_mt_helper, data, 0);
list_add(&pw->pw_list, head);
}
- spin_unlock(&padata_works_lock);
+ spin_unlock_bh(&padata_works_lock);

return i;
}
@@ -126,12 +126,12 @@ static void __init padata_works_free(struct list_head *works)
if (list_empty(works))
return;

- spin_lock(&padata_works_lock);
+ spin_lock_bh(&padata_works_lock);
list_for_each_entry_safe(cur, next, works, pw_list) {
list_del(&cur->pw_list);
padata_work_free(cur);
}
- spin_unlock(&padata_works_lock);
+ spin_unlock_bh(&padata_works_lock);
}

static void padata_parallel_worker(struct work_struct *parallel_work)
--
2.43.0