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AKwUvBw+78pCSrFP76bu9Pf5gJCuDjZaI4a3PEfRNn+O5C2DYrpJjEiemfzgld6cfsJFCaS2OzJAX9BXGvg0tuE=@vger.kernel.org X-Gm-Message-State: AFuF++mAgdzCx2CQwzaxl0CGxQICZXcY6KjEhWFWJU8yhBHmjQDBDkdu c1gI50SJITLgynhzyYD58oZufCyHZBmQh2kAqf+zFUwyatgKgkrfdMs8V9NmS7XN+NnVja0UoX2 50nq4lOwPRLKXPafDSrlJ1Fx2I+9i9XaBp8VB3da0GMmDJc3TSfKGVg8WJ74= 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:c0d4:10b0:6b7:83d6:293f with SMTP id 006d021491bc7-6b783d6301dmr1065951eaf.66.1788523467122; Fri, 04 Sep 2026 05:04:27 -0700 (PDT) Date: Fri, 04 Sep 2026 05:04:27 -0700 In-Reply-To: <6a964b83.99c12218.408a8.0001.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a9ab3cb.9266084e.bf0d7.0668.GAE@google.com> Subject: Re: [syzbot] [ext4?] general protection fault in __bh_submit From: syzbot To: jack@suse.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, pavankumaryalagada@gmail.com, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 9d80aa4617b3 Add linux-next specific files for 20260903 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=15fa38f9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=bb4a32c282cc2ec7 dashboard link: https://syzkaller.appspot.com/bug?extid=41453ea05ab61c075f1f compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17c228f9580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa38f9580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/417a63e8ac61/disk-9d80aa46.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a1d004c189c1/vmlinux-9d80aa46.xz kernel image: https://storage.googleapis.com/syzbot-assets/97413e5bd243/bzImage-9d80aa46.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/21b9bcefd2ef/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=100508f9580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+41453ea05ab61c075f1f@syzkaller.appspotmail.com Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 UID: 0 PID: 4945 Comm: jbd2/sda1-8 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:const_folio_flags include/linux/page-flags.h:345 [inline] RIP: 0010:folio_test_dropbehind include/linux/page-flags.h:600 [inline] RIP: 0010:__bh_submit+0x22d/0x8d0 fs/buffer.c:1109 Code: c1 e8 03 48 89 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 f6 e7 d7 ff 48 89 5c 24 28 48 8b 1b 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 d4 e7 d7 ff 4d 8b 3f 4c 89 fe 48 RSP: 0018:ffffc9000753f868 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff84b9a9a9 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff8880739467a0 RBP: 0000000000009801 R08: ffff8880739467ff R09: 1ffff1100e728cff R10: dffffc0000000000 R11: ffffed100e728d00 R12: dffffc0000000000 R13: ffff888073946780 R14: ffff888076b240e0 R15: 0000000000000008 FS: 0000000000000000(0000) GS:ffff888124cc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffa1d208708 CR3: 000000000eb48000 CR4: 00000000003526f0 Call Trace: jbd2_journal_commit_transaction+0x2285/0x5c80 fs/jbd2/commit.c:751 kjournald2+0x3bc/0x740 fs/jbd2/journal.c:200 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:const_folio_flags include/linux/page-flags.h:345 [inline] RIP: 0010:folio_test_dropbehind include/linux/page-flags.h:600 [inline] RIP: 0010:__bh_submit+0x22d/0x8d0 fs/buffer.c:1109 Code: c1 e8 03 48 89 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 f6 e7 d7 ff 48 89 5c 24 28 48 8b 1b 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 d4 e7 d7 ff 4d 8b 3f 4c 89 fe 48 RSP: 0018:ffffc9000753f868 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff84b9a9a9 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff8880739467a0 RBP: 0000000000009801 R08: ffff8880739467ff R09: 1ffff1100e728cff R10: dffffc0000000000 R11: ffffed100e728d00 R12: dffffc0000000000 R13: ffff888073946780 R14: ffff888076b240e0 R15: 0000000000000008 FS: 0000000000000000(0000) GS:ffff888124cc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffa1d208708 CR3: 000000007f076000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: c1 e8 03 shr $0x3,%eax 3: 48 89 44 24 18 mov %rax,0x18(%rsp) 8: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) d: 74 08 je 0x17 f: 48 89 df mov %rbx,%rdi 12: e8 f6 e7 d7 ff call 0xffd7e80d 17: 48 89 5c 24 28 mov %rbx,0x28(%rsp) 1c: 48 8b 1b mov (%rbx),%rbx 1f: 4c 8d 7b 08 lea 0x8(%rbx),%r15 23: 4c 89 f8 mov %r15,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 4c 89 ff mov %r15,%rdi 34: e8 d4 e7 d7 ff call 0xffd7e80d 39: 4d 8b 3f mov (%r15),%r15 3c: 4c 89 fe mov %r15,%rsi 3f: 48 rex.W --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.