From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4713F319873 for ; Wed, 7 Jan 2026 13:00:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767790822; cv=none; b=dLl5jappQ5eftNl3+HKr3O7ZYLnZLAFEUXpOliWpyT7ySAwwxvKi7KAy8wcKk8HTtVO5+UJbHH3LC4r6mE1c44of4jFTLvaInFDsfHccVsyoF95rpUuKM6ceYYF2XMz7fIfP/NmgmdxdGravhdBEFEHWxPccCr6c5uiwjOGRbu0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767790822; c=relaxed/simple; bh=gjLcioOKjCaArvb7NVQEop76HM4t8V/bf2T2jADtt1U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XL0M28DTd118s7RmMNOKxlL7v0hnq2TNGpqSBuEr7GR/2lfT+FC+KS404NYXnBphn9Wbgzd31YvVMGoPS4EhspcmtKzWIxTZs66rRKChqx68TSKSxaAUBlIMzeM8Tupyf4NJ4mtN9xjoewIwJPTXptEgIbyAuA3MXtWec0y2nWs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=DvfsDV/+; arc=none smtp.client-ip=209.85.128.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="DvfsDV/+" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-477770019e4so17025745e9.3 for ; Wed, 07 Jan 2026 05:00:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1767790818; x=1768395618; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=b8OM/wM0uqGFQsQ0XBq0KDPlvIR+dfDKEQPKcNmmmRA=; b=DvfsDV/+t+DmuITWYJP/WCQHzd4uRUatvyLsinyOClSbHtAwdcM9UekwdbFZOf5cZW hVRZzcrRshB4eB1fjid1nPS01GBXhExZ2giM7eagELOPZsNx5LyptVZnJYky7cutrizG Qy96IYpHJVrqOjT1GQb0D4wP9mSTa9Wa0dPiucm4+yY3pFP+DG5EveYBVLGP8Tu/u79g i6hYAkNSb6SxavRvVyMKawduPQ/9Kqmx03Ty+3VtiXL74juBGhMwHUp1WdyM0G5bR+jz eYppZR6tv55yVJvG01V4JBrubLmegZjUOyxo6UMH+pcAMDDA39AEoy34/XWIgl6QngML uMpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767790818; x=1768395618; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=b8OM/wM0uqGFQsQ0XBq0KDPlvIR+dfDKEQPKcNmmmRA=; b=u8rjMSoNSUAntbZym3GOVtjp+PEDTO7kklCU8W/hg/kYD/y3jWJVV1makvSZ7vLAt3 yRXfcnIrmO1/MuyMSg5SMMzrLBz3/VtQ7QsVkXYbF5ikDufJPdqhoCVrZJZH77onkd9U 1H5KA9TLdV+HNR8iteiWMkThOqFj5rfxw/25CAiv5PQo8EIYztDOgUhvEZbKyov55R1t 3Xzkq6Q/wP3FbGJsIyJ1Jp4niS0DyP/KEpeC5psGsdPxRxtCGmoKIrrmDnUCCx8cO83u qlqKw2kHfR+FeoKCk3b2dDRazKW8QY/rQ9pHhIQhsjwSrZn3qsoTU/EOPN5g/nWd8WEn 5dOg== X-Forwarded-Encrypted: i=1; AJvYcCXYeC9IEYYUgURIEZ8g0WEOYsWNW9XA0dz8RzDVdzkt/Mj4MGB4L8qnGFcuwZWk0oeISMM+ZrGbhOVC2VY=@vger.kernel.org X-Gm-Message-State: AOJu0YxabEqLpQW4UsUa698CkNOlI31IHnhaIwfN7qikSIAsO1qUt62P IZ5/mmdH4g6hgo6UfZpx4u21RDINBB68pKQav/6plbeidiCTUPx5yDWOpTJSCnKCbw0= X-Gm-Gg: AY/fxX7HwwyBcUVayZHlhWqCB1DGmTLFfVzAh04XCEE93uWJwJo1yjFOc1M/rmmh4kL OIpuU7WnwZlOo37u1eBUwfA7kzrEncmEz444kPQ75N5JGrJlNN4wRE/Q2bcEn0GCHe/Ri9Nq4FV ZCNhUMW4azijym0uYU3kgj8a5xE84BeJySEeamnrQlAsU+7ib4mxpkDdi/+9bZderPyNiMpirfP IGUtVZGoKLmI8x/Q8iSXx2XWQd25ERkDUOZR04g5Lyvub/J9kEMLgvVH8ZrkfW8OFh8D7EXZig7 5WghWIhVuncfNag/RRCzWtKWk5PGLEFrWnuRd5xmENp1b7iYIwPRBUUhywIwCR1qcFADiQEJVKJ WSZ1UcOsA9EPPEUCkuVP/bs8mU4WgUU8U0txMNrD0pWoEvNouFzSwRQ8a5qnB1tCvwmS4R6t1bQ itiCvjSxxvbhMxKA== X-Google-Smtp-Source: AGHT+IHXv9yotK6XG/wc2JBKVbd7hMIoqMUXk18WTbSVp9IFsDwfj8PCGizKHMxES3PasjFMQuD/Ng== X-Received: by 2002:a05:600c:c4a8:b0:477:54cd:2030 with SMTP id 5b1f17b1804b1-47d84b32788mr29119595e9.21.1767790818492; Wed, 07 Jan 2026 05:00:18 -0800 (PST) Received: from pathway.suse.cz ([176.114.240.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47d87189e54sm11153655e9.12.2026.01.07.05.00.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jan 2026 05:00:17 -0800 (PST) Date: Wed, 7 Jan 2026 14:00:13 +0100 From: Petr Mladek To: syzbot Cc: anna.luese@v-bien.de, cem@kernel.org, davem@davemloft.net, edumazet@google.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, john.ogness@linutronix.de, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, rostedt@goodmis.org, senozhatsky@chromium.org, syzkaller-bugs@googlegroups.com, xiyou.wangcong@gmail.com Subject: Re: [syzbot] [xfs?] INFO: task hung in xfs_file_fsync Message-ID: References: <686ea951.050a0220.385921.0015.GAE@google.com> <686f0cd3.050a0220.385921.0023.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <686f0cd3.050a0220.385921.0023.GAE@google.com> On Wed 2025-07-09 17:44:03, syzbot wrote: > syzbot has bisected this issue to: > > commit 0161e2d6950fe66cf6ac1c10d945bae971f33667 > Author: John Ogness > Date: Mon Dec 9 11:17:46 2024 +0000 > > printk: Defer legacy printing when holding printk_cpu_sync > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14b19a8c580000 Just for record. It looks to me that the bisection was wrong. The original problem was: ci starts bisection 2025-07-09 13:22:22.587055103 +0000 UTC m=+182.380303436 bisecting cause commit starting from d006330be3f782ff3fb7c3ed51e617e01f29a465 building syzkaller on abade7941e7b8a888e052cda1a92805ab785c77e ensuring issue is reproducible on original commit d006330be3f782ff3fb7c3ed51e617e01f29a465 testing commit d006330be3f782ff3fb7c3ed51e617e01f29a465 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: fd86d90e0d4e2b546bda0ba5ad3009b1c803f92f35eefc7a5a9a6a9779edb44a run #0: crashed: INFO: task hung in xfs_setfilesize run #1: crashed: INFO: task hung in xfs_setfilesize run #2: crashed: INFO: task hung in xfs_setfilesize run #3: crashed: INFO: task hung in process_measurement run #4: crashed: INFO: task hung in xfs_setfilesize run #5: crashed: INFO: task hung in process_measurement run #6: crashed: INFO: task hung in xfs_setfilesize run #7: crashed: INFO: task hung in process_measurement run #8: crashed: INFO: task hung in process_measurement run #9: crashed: INFO: task hung in xfs_setfilesize run #10: crashed: INFO: task hung in xfs_setfilesize run #11: crashed: INFO: task hung in xfs_setfilesize run #12: crashed: INFO: task hung in xfs_setfilesize run #13: crashed: INFO: task hung in xfs_setfilesize run #14: crashed: INFO: task hung in xfs_trans_alloc_inode run #15: crashed: INFO: task hung in xfs_trans_alloc_inode run #16: crashed: INFO: task hung in xfs_setfilesize run #17: crashed: INFO: task hung in xfs_setfilesize run #18: crashed: INFO: task hung in xfs_setfilesize run #19: crashed: INFO: task hung in xfs_setfilesize representative crash: INFO: task hung in xfs_setfilesize, types: [HANG] But the end of the bisection looks like: testing commit 4ca6c022279dddba1eca8ea580c82ea510ecf690 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 03f8650641fe155806b39e47c854b91bf96ee0d5e9d18ff940235c5a21c89620 run #0: OK run #1: OK run #2: OK run #3: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #4: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #5: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #6: OK run #7: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #8: OK run #9: OK run #10: OK run #11: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK representative crash: BUG: MAX_LOCKDEP_KEYS too low!, types: [UNKNOWN] # git bisect bad 4ca6c022279dddba1eca8ea580c82ea510ecf690 Bisecting: 4 revisions left to test after this (roughly 2 steps) [62de6e1685269e1637a6c6684c8be58cc8d4ff38] Merge tag 'sched-core-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip testing commit 62de6e1685269e1637a6c6684c8be58cc8d4ff38 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 8e4e982610da69c055ecca8aaca23f23a454eb4db0ee20d8bf6d5ae22aeebb01 run #0: ignore: lost connection to test machine run #1: OK run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK run #10: OK run #11: OK run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK false negative chance: 0.001 # git bisect good 62de6e1685269e1637a6c6684c8be58cc8d4ff38 Bisecting: 2 revisions left to test after this (roughly 1 step) [0161e2d6950fe66cf6ac1c10d945bae971f33667] printk: Defer legacy printing when holding printk_cpu_sync testing commit 0161e2d6950fe66cf6ac1c10d945bae971f33667 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 7566994b210981fb429e3b5e9ed670407710135484fee131b57299dc8b3071f7 run #0: OK run #1: OK run #2: OK run #3: OK run #4: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #5: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #6: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #7: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #8: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #9: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #10: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #11: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #12: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #13: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #14: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #15: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #16: crashed: BUG: MAX_LOCKDEP_KEYS too low! run #17: OK run #18: OK run #19: OK representative crash: BUG: MAX_LOCKDEP_KEYS too low!, types: [UNKNOWN] # git bisect bad 0161e2d6950fe66cf6ac1c10d945bae971f33667 Bisecting: 0 revisions left to test after this (roughly 0 steps) [f1c21cf470595c4561d4671fd499af94152175d5] printk: Remove redundant deferred check in vprintk() testing commit f1c21cf470595c4561d4671fd499af94152175d5 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: a7cc6b185bdb5074103099a969663e598b6c2f53f61168a0f2e7c1d9bc9e8426 all runs: OK false negative chance: 0.001 # git bisect good f1c21cf470595c4561d4671fd499af94152175d5 0161e2d6950fe66cf6ac1c10d945bae971f33667 is the first bad commit commit 0161e2d6950fe66cf6ac1c10d945bae971f33667 Author: John Ogness Date: Mon Dec 9 12:23:46 2024 +0106 printk: Defer legacy printing when holding printk_cpu_sync Notice: ======= The original test crashed with: crashed: INFO: task hung in xfs_setfilesize But the bad commits around the potential bad commit are failing with crashed: BUG: MAX_LOCKDEP_KEYS too low! Conclusion: =========== I believe that the bisection went into a wrong direction. And the printk() change has nothing to do with a hung task. Best Regards, Petr > start commit: d006330be3f7 Merge tag 'sound-6.16-rc6' of git://git.kerne.. > git tree: upstream > final oops: https://syzkaller.appspot.com/x/report.txt?x=16b19a8c580000 > console output: https://syzkaller.appspot.com/x/log.txt?x=12b19a8c580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da > dashboard link: https://syzkaller.appspot.com/bug?extid=9bc8c0586b39708784d9 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15e24a8c580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10ed3582580000 > > Reported-by: syzbot+9bc8c0586b39708784d9@syzkaller.appspotmail.com > Fixes: 0161e2d6950f ("printk: Defer legacy printing when holding printk_cpu_sync") > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection