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From: Dominique Martinet <asmadeus@codewreck.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: syzbot <syzbot+d1b5dace43896bc386c3@syzkaller.appspotmail.com>,
	David Howells <dhowells@redhat.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	akpm@linux-foundation.org, brauner@kernel.org,
	dvyukov@google.com, elver@google.com, glider@google.com,
	jack@suse.cz, kasan-dev@googlegroups.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, syzkaller-bugs@googlegroups.com,
	viro@zeniv.linux.org.uk, willy@infradead.org
Subject: Re: [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync
Date: Tue, 19 Aug 2025 06:55:13 +0900	[thread overview]
Message-ID: <aKOhQcVwLd1Kvt6N@codewreck.org> (raw)
In-Reply-To: <20250818125625.GC18626@redhat.com>

Hi Oleg,

Oleg Nesterov wrote on Mon, Aug 18, 2025 at 02:56:26PM +0200:
> On 08/18, syzbot wrote:
> > syzbot has tested the proposed patch and the reproducer did not trigger any issue:

(I hate that syzbot identified "hung in v9fs_file_fsync" but doesn't
bother to Cc 9p folks... all the time..)

> Dominique, David,
> 
> Perhaps you can reconsider the fix that Prateek and I tried to propose
> in this thread
> 
> 	[syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter
> 	https://lore.kernel.org/all/67dedd2f.050a0220.31a16b.003f.GAE@google.com/

I've re-read that thread, and I still think this must be a problem
specific to syzbot doing obviously bogus things (e.g. replying before
request, or whatever it is this particular repro is doing), but I guess
your patch is also sane enough and the 9p optimization is probably not
really needed here

Please resend as a proper patch, and I'll just run some quick check (and
a trivial benchmark) and pick it up

Thanks,
-- 
Dominique Martinet | Asmadeus

  reply	other threads:[~2025-08-18 21:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-18  8:04 [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync syzbot
2025-08-18 11:44 ` Oleg Nesterov
2025-08-18 12:36   ` syzbot
2025-08-18 12:56     ` Oleg Nesterov
2025-08-18 21:55       ` Dominique Martinet [this message]
2025-08-18 13:04     ` Oleg Nesterov
2025-08-19 16:10 ` [PATCH] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN Oleg Nesterov
2025-08-19 16:13   ` Oleg Nesterov
2025-08-20  6:29   ` K Prateek Nayak

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