| Message ID | Zg0jEu5OsZaUFzn0@gondor.apana.org.au (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | padata: Disable BH when taking works lock on MT path | expand |
On Wed, Apr 03, 2024 at 05:36:18PM +0800, Herbert Xu wrote: > On Mon, Apr 01, 2024 at 07:08:28AM -0700, syzbot wrote: > > > > syzbot found the following issue on: > > > > HEAD commit: 18737353cca0 Merge tag 'edac_urgent_for_v6.9_rc2' of git:/.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=15d605e5180000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=f64ec427e98bccd7 > > dashboard link: https://syzkaller.appspot.com/bug?extid=0cb5bb0f4bf9e79db3b3 > > compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > > Strictly speaking this can't happen because for the time being > padata_do_multithreaded cannot run at the same time as the old > padata which occurs in BH context. > > But the simplest fix is to just disable BH: > > ---8<--- > 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>
diff --git a/kernel/padata.c b/kernel/padata.c index e3f639ff1670..53f4bc912712 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -106,7 +106,7 @@ 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(); @@ -116,7 +116,7 @@ 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; } @@ -134,12 +134,12 @@ 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)