From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from nautica.notk.org (nautica.notk.org [91.121.71.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A84F722F17 for ; Sun, 28 Jan 2024 13:15:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.121.71.147 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706447704; cv=none; b=HZKgOl/dAkPkE5MJh9D9ULRq/uJOJcdF7Gi6q7F+vqD+cyKZkf8R7MIlPwFcwiDX9giZMGERyUuEjdYeU33ijIJlyoSvjHSiLE5L2EO88QlSYugB7gX9+/CZJOz5LE7TbbqsnkmbLbWUsV+BniH29TWe9wRv/EA8xEGuFmuEpr0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706447704; c=relaxed/simple; bh=47IquW87I/pYxtJv9yD8P/bxu0UAKJOwTXCmSSuWj1w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NjRmBrHJP9novzBIZZUqJebN3CncxrgYVFLRHISNzBB3PsC86Po3S6dR/gOSQFdDkRORLv8Xn7/gVnNTi0t2qHi5dlsET/9pCi5MOZ7aZCa/3SLizT6Ivy6chet7Ht3cjau76dupIRiIQ9I8KIJpKuHCgUgkvi6l5mKyn9NK6z8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=qgYpPG+k; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=lGIznWcO; arc=none smtp.client-ip=91.121.71.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="qgYpPG+k"; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="lGIznWcO" Received: by nautica.notk.org (Postfix, from userid 108) id 64C69C009; Sun, 28 Jan 2024 14:06:35 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1706447195; bh=xQ/vOvP/yvllm4fmci5fqe4uqdG9E9f7VwM1xY0YilI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qgYpPG+kRezgbQWeZhElGYzqZaOcU9yUZkw1xlHCO64yu6cIe/dfhSOpiG9R0+YmI IFuyKAq5MRLO/OzHHVvaMGfDUWNiUVUSVlDP/gsq//8r+0Pv0V61YkOl7PwXUMvFyT Huxub5dhmF/HT4UttuXJugVlUHX7OJ3xMb6hscmblZCCNw7MQNfz7aKtiv4XfMO5X2 UR8qecnspn/D4TZZKBhVlbeXnW04SKMNQvUQK3xR22kQIppWN9KJZ28y5EwaYvR3v5 vRi6o6/hT33Ut2++lLnRRzl14JD1je4DpVcOEr+l5iFCpx9L2kT/Xzvjmx98rRvXHV m67X0GkDCYwOA== X-Spam-Level: Received: from gaia.codewreck.org (localhost [127.0.0.1]) by nautica.notk.org (Postfix) with ESMTPS id 53BBEC009; Sun, 28 Jan 2024 14:06:33 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1706447194; bh=xQ/vOvP/yvllm4fmci5fqe4uqdG9E9f7VwM1xY0YilI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lGIznWcOBscmNQLj40tSUi7k50Bz+USnLQf+26oJBNRegyAWQjVxaZjQpfhjEFgWZ ozsc6csjP4yZ3hXsXFB0W7xeminVYxJp621S1W8xwl3b55b6xb3fdVVK+XG2No2f5d Is/Eqx8TBLmiCPaXEjdIE2YPYRG0eBltODJwbVYApVx1991vFge+8aNh3NXNyOMhTf s4bxZGB9vlZiiYy+BwfCC6lIuXMqQFVPQJV0Gg06k5F6ovtSw+Y7248hyX4loxrY32 6mW+p41c48HWyeEs4o+n9MpielkOR59OlBZ+bz+WoL+i6DQetYwYbyvZ5MMPmOJ85F PYATip+R2mcoA== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 1c2c40f1; Sun, 28 Jan 2024 13:06:27 +0000 (UTC) Date: Sun, 28 Jan 2024 22:06:12 +0900 From: Dominique Martinet To: dhowells@redhat.com, Eric Van Hensbergen Cc: v9fs@lists.linux.dev, linux_oss@crudebyte.com Subject: Re: fs/9p: regression in 6.8-rc1 Message-ID: References: Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Dominique Martinet wrote on Sat, Jan 27, 2024 at 10:53:19AM +0900: > Eric Van Hensbergen wrote on Fri, Jan 26, 2024 at 02:21:39PM -0600: > > I caught a problem in the new netfs code when running in 9p when running > > with nocache mode. A regression sweep is turning up a: > > [ 1084.438387] netfs: Zero-sized write [R=1b6da] > > when running my ldconfig test (included at the end of this) > > it reports: > > /sbin/ldconfig.real: Writing of cache extension data failed: Input/output error > > > > I will try to dig into this later today if I have time, but not sure I'll get > > to it so I wanted to make other folks aware. I'm not sure how much other > > elements of my test harness are contributing to reproducing the problem. Didn't get much time, I can just confirm I can reproduce, it boils down to a 0-size write: $ xfs_io -f -c 'pwrite 0 0' foo (dmesg) netfs: Zero-sized write [R=fb5] pwrite: Input/output error I was going to say we probably need to filter it out - but it looks like that might be netfs' job given the call trace I get: # retsnoop -T -e vfs_write -a :fs/9p/*.c -a :fs/netfs/*.c FUNCTION CALL TRACE RESULT DURATION --------------------------------- -------------------- ---------- → vfs_write → netfs_unbuffered_write_iter ↔ netfs_start_io_direct [0] 0.391us → netfs_alloc_request ↔ v9fs_init_request [0] 0.431us ← netfs_alloc_request [0xffff8b8a5584d600] 1.653us ↔ netfs_extract_user_iter [0] 0.671us → netfs_begin_write ↔ v9fs_free_inode [void] 33.653us ↔ v9fs_free_inode [void] 0.511us ↔ v9fs_free_inode [void] 0.371us ↔ v9fs_free_inode [void] 0.350us ↔ v9fs_free_inode [void] 0.391us ↔ v9fs_free_inode [void] 0.361us ↔ v9fs_free_inode [void] 0.451us ↔ v9fs_free_inode [void] 0.391us ↔ v9fs_free_inode [void] 0.391us ↔ v9fs_free_inode [void] 0.451us ← netfs_begin_write [-EIO] 1120.811us → netfs_free_request ↔ v9fs_free_request [void] 28.062us ← netfs_free_request [void] 44.423us ↔ netfs_end_io_direct [void] 0.421us ← netfs_unbuffered_write_iter [-EIO] 1207.784us ← vfs_write [-EIO] 1210.228us David, where do you think we should catch that? Can we leave that fix to you? > The syzbot report (refcount underflow[1]) is also probably related; I'll > try to find some time to check a bit more this weekend > > [1] https://lkml.kernel.org/r/000000000000ee5c6c060fd59890@google.com So that one's not directly related to this, but given the timing I'd still bet something changed around cache... I didn't manage to reproduce it on a very quick workload but I didn't run all that much yet, will need to spend a bit more time on that another day... -- Dominique Martinet | Asmadeus