From nobody Fri Dec 19 13:27:49 2025 Received: from mail-oo1-f70.google.com (mail-oo1-f70.google.com [209.85.161.70]) (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 605C9178372 for ; Sat, 6 Dec 2025 08:03:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.70 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765008214; cv=none; b=NOvu6GfCSpxk1Qv46N0/xu/C/8TYYpo7lKdYPtjEj68IvB/Qg+y3WTdh70EN0+HHOodsnDniK2A6ay9iP4E1hnH6qwABdehfFMQpmInferzFfdNR8IE9X5QguZkKThuKTuSHEKoGmQ0bdCZoncrAubE2+rJOdNiTG8YOcQLFR3U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765008214; c=relaxed/simple; bh=kJlWs2G+rH9pAzRUlWCY0p2T7YUEdaX01P8Ban9Mkzg=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=SoP3uZvcfQ9+FNr1vhIF3h6H2dQN4qIb78Ag4h+eAsQ0K2sJapgqiAJnbUYlPpbpQ9M+4DOp8AHYbWoAfnYIqY9k0Q1b8sbQx2LHipJ+Ajt997tsH4p6lRBF3NfmLam07s+TZ/ZpSOz3b5KUPA6obhtjr9ZEWNHh3Ep3MCF9/iI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f70.google.com with SMTP id 006d021491bc7-6574d366132so2013270eaf.0 for ; Sat, 06 Dec 2025 00:03:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765008211; x=1765613011; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MTZlGgaZeZJTBJ3DVotxx5K1j5OvK3MJdimOH/ZFQhs=; b=aFMqv2XneaewzNl76ZS5W/xU7ww8ZSAzJCBq9al2i/l37fR/frFmx4LU4zmGsbFt12 Hp6QMDVqenD5HcUhtSucrwDIkk92wjj8qdkvQG9UghxD4NHYDY3z/pnIyJVExtjTlKGz I5UkIZ5zto3V/CgcjZH91w8Eqbu61fl161zgU5AQ7glppLWxwLiYqe7P9Sg3XGyuxBHg kS5Nuv0EgYQt78D5PcgpTCp8UH5nEHHPUU6mfaDfZVQD+k4AUMcJsFSffb8F+b/v48sg 23uqrPuEmi68mzQ46/LxSKKkuoLfY9dk1tZ/lGlngsXccx89CI85EB7xg1ukoKaljUhM hMew== X-Gm-Message-State: AOJu0YwhiFEG1/w52QTXnK/iL5SD3wlbLwbNwH1nUtyoOypHY+IM9Nti IEfEl4o4xI5O2jnYizavx/Syp2Ae2YqeEXuwZQkzedHKUkPxiRNfR8aLwpHbQ5aCxVrEK9JQDes BINAQw8Zf3Amh5trlwQz5AYIKXRgV1opH6Q9Ndf1j0x5HnoDjSJKil2rsAlg= X-Google-Smtp-Source: AGHT+IH/H8chqbz89DuMw53aGCsSkio1qhzrMYRdUe+xrZNLnMJwcXpD200gHpPfReT8OBp2rc+Fciq30Rf7u5O2PnmeJz3p7qQI Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:220d:b0:659:9a49:8e56 with SMTP id 006d021491bc7-6599a94aef1mr740792eaf.38.1765008211583; Sat, 06 Dec 2025 00:03:31 -0800 (PST) Date: Sat, 06 Dec 2025 00:03:31 -0800 In-Reply-To: <69332cf9.a70a0220.243dc6.0011.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6933e353.a70a0220.38f243.0019.GAE@google.com> Subject: Forwarded: [PATCH] f2fs: fix hung task in block_operations during checkpoint From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] f2fs: fix hung task in block_operations during checkpoint Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git= master f2fs_sync_inode_meta() can return 0 (success) even when f2fs_update_inode_page() fails and triggers f2fs_stop_checkpoint(). This happens because the error flag check only occurs at the start of each loop iteration, not after f2fs_update_inode_page() returns. When I/O errors occur: 1. f2fs_update_inode_page() retries 8 times then calls f2fs_stop_checkpoint(), which sets CP_ERROR_FLAG 2. f2fs_sync_inode_meta() returns 0 without checking the error flag 3. block_operations() sees success and loops back to retry_flush_qu= otas 4. Dirty inodes remain on list (sync failed), loop repeats forever 5. Checkpoint never completes, waiters block indefinitely This causes hung tasks when operations like unlink wait for checkpo= int completion while holding locks that other tasks need. Fix by checking f2fs_cp_error() after processing each inode in f2fs_sync_inode_meta() to detect errors from f2fs_update_inode_page= (). Reported-by: syzbot+4235e4d7b6fd75704528@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D4235e4d7b6fd75704= 528 Signed-off-by: Deepanshu Kartikey --- fs/f2fs/checkpoint.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index bbe07e3a6c75..b0b5b792e092 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1659,9 +1659,10 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, = struct cp_control *cpc) return 0; f2fs_warn(sbi, "Start checkpoint disabled!"); } + printk("f2fs_cp: 1 before cp_global_sem\n"); if (cpc->reason !=3D CP_RESIZE) f2fs_down_write(&sbi->cp_global_sem); - + printk("f2fs_cp: 2 after cp_global_sem\n"); stat_cp_time(cpc, CP_TIME_LOCK); =20 if (!is_sbi_flag_set(sbi, SBI_IS_DIRTY) && @@ -1669,16 +1670,18 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi,= struct cp_control *cpc) ((cpc->reason & CP_DISCARD) && !sbi->discard_blks))) goto out; if (unlikely(f2fs_cp_error(sbi))) { + printk("f2fs_cp: 3 cp_error detected early\n"); err =3D -EIO; goto out; } =20 trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "start block_ops"); - + printk("f2fs_cp: 4 before block_operations\n"); err =3D block_operations(sbi); + printk("f2fs_cp: 5 after block_operations err=3D%d cp_error=3D%d\n", err,= f2fs_cp_error(sbi)); if (err) goto out; - + //printk("f2fs_cp: 6 before do_checkpoint\n"); stat_cp_time(cpc, CP_TIME_OP_LOCK); =20 trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish block_ops"); @@ -1724,8 +1727,10 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, = struct cp_control *cpc) =20 /* save inmem log status */ f2fs_save_inmem_curseg(sbi); + printk("f2fs_cp: 4 before block_operations\n"); =20 err =3D do_checkpoint(sbi, cpc); + printk("f2fs_cp: 7 after do_checkpoint err=3D%d\n", err); if (err) { f2fs_err(sbi, "do_checkpoint failed err:%d, stop checkpoint", err); f2fs_bug_on(sbi, !f2fs_cp_error(sbi)); --=20 2.43.0