On Mon, Nov 3, 2025 at 6:43 PM syzbot <[email protected]> wrote: > > Hello, > > syzbot has tested the proposed patch but the reproducer is still triggering > an issue: > WARNING in get_data > > loop0: detected capacity change from 0 to 16 > ------------[ cut here ]------------ > WARNING: kernel/printk/printk_ringbuffer.c:1278 at get_data+0x48a/0x840 > kernel/printk/printk_ringbuffer.c:1278, CPU#1: syz.0.585/7652 > Modules linked in: > CPU: 1 UID: 0 PID: 7652 Comm: syz.0.585 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 10/02/2025 > RIP: 0010:get_data+0x48a/0x840 kernel/printk/printk_ringbuffer.c:1278 > Code: 83 c4 f8 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 07 84 c0 0f 85 ee 01 > 00 00 44 89 65 00 49 83 c5 08 eb 13 e8 a7 19 1f 00 90 <0f> 0b 90 eb 05 e8 9c > 19 1f 00 45 31 ed 4c 89 e8 48 83 c4 28 5b 41 > RSP: 0018:ffffc900035170e0 EFLAGS: 00010293 > RAX: ffffffff81a1eee9 RBX: 00003fffffffffff RCX: ffff888033255b80 > RDX: 0000000000000000 RSI: 00003fffffffffff RDI: 0000000000000000 > RBP: 0000000000000012 R08: 0000000000000e55 R09: 000000325e213cc7 > R10: 000000325e213cc7 R11: 00001de4c2000037 R12: 0000000000000012 > R13: 0000000000000000 R14: ffffc90003517228 R15: 1ffffffff1bca646 > FS: 00007f44eb8da6c0(0000) GS:ffff888125fda000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f44ea9722e0 CR3: 0000000066344000 CR4: 00000000003526f0 > Call Trace: > <TASK> > copy_data kernel/printk/printk_ringbuffer.c:1857 [inline] > prb_read kernel/printk/printk_ringbuffer.c:1966 [inline] > _prb_read_valid+0x672/0xa90 kernel/printk/printk_ringbuffer.c:2143 > prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2215 > printk_get_next_message+0x15c/0x7b0 kernel/printk/printk.c:2978 > console_emit_next_record kernel/printk/printk.c:3062 [inline] > console_flush_one_record kernel/printk/printk.c:3194 [inline] > console_flush_all+0x4cc/0xb10 kernel/printk/printk.c:3268 > __console_flush_and_unlock kernel/printk/printk.c:3298 [inline] > console_unlock+0xbb/0x190 kernel/printk/printk.c:3338 > vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 > _printk+0xcf/0x120 kernel/printk/printk.c:2448 > _erofs_printk+0x349/0x410 fs/erofs/super.c:33 > erofs_fc_fill_super+0x1591/0x1b20 fs/erofs/super.c:746 > get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 > vfs_get_tree+0x92/0x2b0 fs/super.c:1752 > fc_mount fs/namespace.c:1198 [inline] > do_new_mount_fc fs/namespace.c:3641 [inline] > do_new_mount+0x302/0xa10 fs/namespace.c:3717 > do_mount fs/namespace.c:4040 [inline] > __do_sys_mount fs/namespace.c:4228 [inline] > __se_sys_mount+0x313/0x410 fs/namespace.c:4205 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f44ea99076a > Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 > 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 > 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f44eb8d9e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007f44eb8d9ef0 RCX: 00007f44ea99076a > RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007f44eb8d9eb0 > RBP: 0000200000000180 R08: 00007f44eb8d9ef0 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000001c0 > R13: 00007f44eb8d9eb0 R14: 00000000000001a1 R15: 0000200000000080 > </TASK> >
This looks unrelated to the iomap changes and seems tied to the recent printk console flushing changes. Hmm, maybe one of these changes [1,2,3]? ccing Andrew and Petr, who would know more [1] https://lore.kernel.org/all/20251020-printk_legacy_thread_console_lock-v3-1-00f1f0ac0...@thegoodpenguin.co.uk/ [2] https://lore.kernel.org/all/20251020-printk_legacy_thread_console_lock-v3-2-00f1f0ac0...@thegoodpenguin.co.uk/ [3] https://lore.kernel.org/all/20251020-printk_legacy_thread_console_lock-v3-3-00f1f0ac0...@thegoodpenguin.co.uk/ Thanks, Joanne > > Tested on: > > commit: 98231209 Add linux-next specific files for 20251103 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1370a292580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=43cc0e31558cb527 > dashboard link: https://syzkaller.appspot.com/bug?extid=3686758660f980b402dc > compiler: Debian clang version 20.1.8 > (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > > Note: no patches were applied. _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
