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AJvYcCXYt8tithwY8A1wfBFItHtiXnsMensLKI3yNLCJqC/chk9xE1ExPPz7Vb4na7h7QDLFRyuYzdy7ZSUB@vger.kernel.org X-Gm-Message-State: AOJu0YxgnizprFRJ/G1dGzrX74ZFrcyOdlu6rGl0FoDQ2wLBg0wLx6K0 iebrAmeiZxrXkhuymmIEgSllVb2Q1WLC8eMgBo23lma2asKQ5JW6u23EIyOlWCN1x0k/rsO4tTU GurVJz7wynyx7HrYlqZrdf++dgImzPKM3JUxAAJYQ2p1B8GLl+Tm3OdgWM6U= Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:818b:b0:662:f42e:7cfe with SMTP id 006d021491bc7-66d0bea535fmr4513048eaf.54.1770602907333; Sun, 08 Feb 2026 18:08:27 -0800 (PST) Date: Sun, 08 Feb 2026 18:08:27 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6989419b.050a0220.3b3015.0065.GAE@google.com> Subject: [syzbot] [ext4?] kernel BUG in ext4_es_cache_extent (4) From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 0f8a890c4524 Add linux-next specific files for 20260204 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=12d547fa580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c09aefae2687abea dashboard link: https://syzkaller.appspot.com/bug?extid=ccf1421545dbe5caa20c compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16420a52580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/3c923d50ef46/disk-0f8a890c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3a560206fcf3/vmlinux-0f8a890c.xz kernel image: https://storage.googleapis.com/syzbot-assets/e0826a2ee028/bzImage-0f8a890c.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/4532e6e390d7/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1533aa5a580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ccf1421545dbe5caa20c@syzkaller.appspotmail.com EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #18: comm syz.0.37: ES cache extent failed: add [22,10,230,0x1] conflict with existing [17,15,145,0x2] EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #18: comm syz.0.37: ES cache extent failed: add [32,1,353,0x1] conflict with existing [32,1,161,0x2] EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #18: comm syz.0.37: ES cache extent failed: add [33,15,353,0x1] conflict with existing [33,15,161,0x2] ------------[ cut here ]------------ kernel BUG at fs/ext4/extents_status.c:1044! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 6168 Comm: syz.0.37 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:ext4_es_cache_extent+0x875/0x9e0 fs/ext4/extents_status.c:1044 Code: e1 07 80 c1 03 38 c1 0f 8c 5c fe ff ff 48 8b 7c 24 18 e8 7e 15 ae ff e9 4d fe ff ff e8 a4 32 44 ff 90 0f 0b e8 9c 32 44 ff 90 <0f> 0b 65 8b 1d f6 c4 99 10 bf 07 00 00 00 89 de e8 c6 36 44 ff 83 RSP: 0018:ffffc90003dedb80 EFLAGS: 00010293 RAX: ffffffff82816b34 RBX: 0000000000000023 RCX: ffff8880271c9e40 RDX: 0000000000000000 RSI: 0000000000000030 RDI: 0000000000000023 RBP: ffffc90003dedcc8 R08: ffffc90003dedc37 R09: 0000000000000000 R10: ffffc90003dedc20 R11: fffff520007bdb87 R12: ffffc90003dedc20 R13: 0000000000000030 R14: 000000000000000f R15: dffffc0000000000 FS: 000055556ddfe500(0000) GS:ffff88812546d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f56b9c15000 CR3: 0000000079388000 CR4: 00000000003526f0 Call Trace: ext4_cache_extents fs/ext4/extents.c:539 [inline] __read_extent_tree_block+0x4b4/0x890 fs/ext4/extents.c:586 ext4_find_extent+0x76b/0xcc0 fs/ext4/extents.c:941 ext4_ext_map_blocks+0x283/0x58b0 fs/ext4/extents.c:4263 ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809 _ext4_get_block+0x1e3/0x470 fs/ext4/inode.c:909 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:942 ext4_block_write_begin+0xb14/0x1950 fs/ext4/inode.c:1196 ext4_write_begin+0xb40/0x18c0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x355/0xd80 fs/ext4/inode.c:3123 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:300 ext4_file_write_iter+0x298/0x1bf0 fs/ext4/file.c:-1 __kernel_write_iter+0x41e/0x880 fs/read_write.c:621 dump_emit_page fs/coredump.c:1299 [inline] dump_user_range+0xb89/0x12d0 fs/coredump.c:1373 elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2111 coredump_write+0x1219/0x1950 fs/coredump.c:1050 do_coredump fs/coredump.c:1127 [inline] vfs_coredump+0x36a9/0x4280 fs/coredump.c:1201 get_signal+0x1107/0x1330 kernel/signal.c:3019 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x176/0x620 kernel/entry/common.c:219 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 002b:0000200000000548 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007efd00215fa0 RCX: 00007efcfff9aeb9 RDX: 0000000000000000 RSI: 0000200000000540 RDI: 0000000000000000 RBP: 00007efd00008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efd00215fac R14: 00007efd00215fa0 R15: 00007efd00215fa0 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_es_cache_extent+0x875/0x9e0 fs/ext4/extents_status.c:1044 Code: e1 07 80 c1 03 38 c1 0f 8c 5c fe ff ff 48 8b 7c 24 18 e8 7e 15 ae ff e9 4d fe ff ff e8 a4 32 44 ff 90 0f 0b e8 9c 32 44 ff 90 <0f> 0b 65 8b 1d f6 c4 99 10 bf 07 00 00 00 89 de e8 c6 36 44 ff 83 RSP: 0018:ffffc90003dedb80 EFLAGS: 00010293 RAX: ffffffff82816b34 RBX: 0000000000000023 RCX: ffff8880271c9e40 RDX: 0000000000000000 RSI: 0000000000000030 RDI: 0000000000000023 RBP: ffffc90003dedcc8 R08: ffffc90003dedc37 R09: 0000000000000000 R10: ffffc90003dedc20 R11: fffff520007bdb87 R12: ffffc90003dedc20 R13: 0000000000000030 R14: 000000000000000f R15: dffffc0000000000 FS: 000055556ddfe500(0000) GS:ffff88812556d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00426e000 CR3: 0000000079388000 CR4: 00000000003526f0 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup