On 10/30/19 1:44 AM, syzbot wrote: > syzbot has bisected this bug to: > > commit ef0524d3654628ead811f328af0a4a2953a8310f > Author: Jens Axboe <axboe@xxxxxxxxx> > Date: Thu Oct 24 13:25:42 2019 +0000 > > io_uring: replace workqueue usage with io-wq > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16acf5d0e00000 > start commit: c57cf383 Add linux-next specific files for 20191029 > git tree: linux-next > final crash: https://syzkaller.appspot.com/x/report.txt?x=15acf5d0e00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=11acf5d0e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=cb86688f30db053d > dashboard link: https://syzkaller.appspot.com/bug?extid=221cc24572a2fed23b6b > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168671d4e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=140f4898e00000 > > Reported-by: syzbot+221cc24572a2fed23b6b@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: ef0524d36546 ("io_uring: replace workqueue usage with io-wq") Good catch, it's a case of NULL vs ERR_PTR() confusion. I'll fold in the below fix. diff --git a/fs/io_uring.c b/fs/io_uring.c index af1937d66aee..76d653085987 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3534,8 +3534,9 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, /* Do QD, or 4 * CPUS, whatever is smallest */ concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); ctx->io_wq = io_wq_create(concurrency, ctx->sqo_mm); - if (!ctx->io_wq) { - ret = -ENOMEM; + if (IS_ERR(ctx->io_wq)) { + ret = PTR_ERR(ctx->io_wq); + ctx->io_wq = NULL; goto err; } -- Jens Axboe
