[syzbot] [gfs2?] INFO: task hung in gfs2_recover_journal (4)

[syzbot] [gfs2?] INFO: task hung in gfs2_recover_journal (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    785f0eb2f85d Add linux-next specific files for 20260320
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11b352f6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c584910d0d74158d
dashboard link: https://syzkaller.appspot.com/bug?extid=9013411dc43f3582823a
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=15b352f6580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1528aada580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a1f7fd9c1a63/disk-785f0eb2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c138da87c25/vmlinux-785f0eb2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4d1be64e56db/bzImage-785f0eb2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/b8d9a874b489/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16fc7ada580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9013411dc43f3582823a@syzkaller.appspotmail.com

INFO: task kworker/0:3:5963 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:3     state:D stack:25400 pid:5963  tgid:5963  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: gfs2_recovery gfs2_recover_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x165c/0x5560 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 io_schedule+0x7f/0xd0 kernel/sched/core.c:7889
 folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1324
 folio_wait_locked include/linux/pagemap.h:1245 [inline]
 gfs2_jhead_process_page+0x175/0x670 fs/gfs2/lops.c:470
 gfs2_find_jhead+0xbd2/0xd30 fs/gfs2/lops.c:586
 gfs2_recover_func+0x6cf/0x1f60 fs/gfs2/recovery.c:459
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3288
 process_scheduled_works kernel/workqueue.c:3379 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.0.18:6005 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.18        state:D stack:24120 pid:6005  tgid:6005  ppid:5953   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x165c/0x5560 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 bit_wait+0x11/0xd0 kernel/sched/wait_bit.c:240
 __wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
 wait_on_bit include/linux/wait_bit.h:77 [inline]
 gfs2_recover_journal+0xda/0x140 fs/gfs2/recovery.c:579
 init_journal+0x16ad/0x2280 fs/gfs2/ops_fstype.c:794
 init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:844
 gfs2_fill_super+0x1a38/0x21d0 fs/gfs2/ops_fstype.c:1250
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3764 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3840
 do_mount fs/namespace.c:4173 [inline]
 __do_sys_mount fs/namespace.c:4372 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4349
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f611259da0a
RSP: 002b:00007ffe1764d4e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe1764d570 RCX: 00007f611259da0a
RDX: 0000200000037f40 RSI: 0000200000037f80 RDI: 00007ffe1764d530
RBP: 0000200000037f40 R08: 00007ffe1764d570 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000037f80
R13: 00007ffe1764d530 R14: 0000000000037fc4 R15: 0000200000000300
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
1 lock held by khungtaskd/30:
 #0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5600:
 #0: ffff888037d8f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
2 locks held by kworker/0:3/5963:
 #0: ffff8880232a6140 ((wq_completion)gfs2_recovery){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3260
 #1: ffffc900043b7c40 ((work_completion)(&jd->jd_work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3261
1 lock held by syz.0.18/6005:
 #0: ffff8880346ce0d8 (&type->s_umount_key#54/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:345
3 locks held by syz.1.203/6599:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd3/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6599 Comm: syz.1.203 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:mark_lock+0xa4/0x190 kernel/locking/lockdep.c:4774
Code: 0e 48 c7 c6 19 03 06 8e 67 48 0f b9 3a 90 31 c9 4c 89 fe 4c 89 f7 b8 01 00 00 00 85 69 60 74 10 5b 41 5c 41 5d 41 5e 41 5f 5d <c3> cc cc cc cc cc 49 89 fe 49 89 f7 e8 5b 94 ff ff 89 c1 31 c0 85
RSP: 0018:ffffc90000a08840 EFLAGS: 00000006
RAX: 0000000000000001 RBX: ffff88801d3dc8e8 RCX: ffffffff93c65330
RDX: 0000000000000008 RSI: ffff88801d3dc8c8 RDI: ffff88801d3dbd00
RBP: ffff88801d3dc8c8 R08: ffffffff84b9d570 R09: ffffffff9a4fdcb8
R10: ffffc90000a08a60 R11: fffff5200014114e R12: 0000000000000003
R13: ffff88801d3dc8c8 R14: ffff88801d3dbd00 R15: 0000000000000003
FS:  000055557c000500(0000) GS:ffff888125548000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055910e737168 CR3: 000000006c700000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 mark_usage kernel/locking/lockdep.c:4674 [inline]
 __lock_acquire+0x6b5/0x2cf0 kernel/locking/lockdep.c:5191
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 debug_object_assert_init+0xb0/0x370 lib/debugobjects.c:1035
 debug_timer_assert_init kernel/time/timer.c:803 [inline]
 debug_assert_init kernel/time/timer.c:848 [inline]
 __mod_timer+0x4a/0xf30 kernel/time/timer.c:1025
 dsp_cmx_send+0x1abe/0x1b40 drivers/isdn/mISDN/dsp_cmx.c:1839
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x22a/0x840 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:739
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:756
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2039 [inline]
RIP: 0010:vprintk_emit+0x45d/0x560 kernel/printk/printk.c:2478
Code: 0f 84 44 ff ff ff e8 a2 09 21 00 fb eb 44 e8 9a 09 21 00 e8 75 7b 0b 0a 4d 85 f6 74 94 e8 8b 09 21 00 fb 48 c7 c7 00 fc 74 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 cb 18
RSP: 0018:ffffc90004b06e00 EFLAGS: 00000293
RAX: ffffffff81a547f5 RBX: ffffffff81a5466f RCX: ffff88801d3dbd00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e74fc00
RBP: ffffc90004b06eb0 R08: ffffffff90123cf7 R09: 1ffffffff202479e
R10: dffffc0000000000 R11: fffffbfff202479f R12: 0000000000000000
R13: 000000000000002f R14: 0000000000000200 R15: 1ffff92000960dc4
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 set_capacity_and_notify+0x2c5/0x320 block/genhd.c:93
 loop_set_size+0x44/0xb0 drivers/block/loop.c:220
 loop_configure+0x9ac/0xdf0 drivers/block/loop.c:1079
 lo_ioctl+0x447/0x1fb0 drivers/block/loop.c:1534
 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:804
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa17279c42b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007ffde9d10a80 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fa17279c42b
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffde9d10bb0 R14: 00007ffde9d10b70 R15: 00007fa169800000
 </TASK>


---
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[PATCH] gfs2: prevent corrupt data from entering jextent

[Edward Adam Davis]

During the mount process, when the journal recovery is executed, the
system blocks and waits for the recovery to complete. The issue reported
in [1] involves the kernel thread responsible for journal recovery
becoming blocked on a specific folio that had not yet been fully read.
This folio was submitted via a bio chain containing an excessively large
sector value; however, the submission failed during the process because
the end-of-file (EOF) check for the bio failed. Consequently, the folio
was never unlocked, which ultimately triggered the timeout issue reported
in [1].

To address this, a check for the blocknr value has been added during the
loading of journal extents from the disk. If the blocknr value exceeds
the maximum sector value supported by the disk, it indicates that the
data on the disk is corrupted; in such cases, the loading of the journal
extent is immediately terminated.

[1]
INFO: task kworker/0:3:5963 blocked in I/O wait for more than 143 seconds.
Workqueue: gfs2_recovery gfs2_recover_func
Call Trace:
 folio_wait_locked include/linux/pagemap.h:1245 [inline]
 gfs2_jhead_process_page+0x175/0x670 fs/gfs2/lops.c:470
 gfs2_find_jhead+0xbd2/0xd30 fs/gfs2/lops.c:586
 gfs2_recover_func+0x6cf/0x1f60 fs/gfs2/recovery.c:459

Fixes: b50f227bddf1 ("GFS2: Clean up journal extent mapping")
Reported-by: syzbot+9013411dc43f3582823a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9013411dc43f3582823a
Tested-by: syzbot+9013411dc43f3582823a@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/gfs2/bmap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 1cd8ec0bce83..d42307ab0684 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -2266,6 +2266,9 @@ int gfs2_map_journal_extents(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
 	u64 size;
 	int rc;
 	ktime_t start, end;
+	struct super_block *sb = sdp->sd_vfs;
+	sector_t maxsector = bdev_nr_sectors(sb->s_bdev);
+	u32 bshift = sdp->sd_fsb2bb_shift;
 
 	start = ktime_get();
 	lblock_stop = i_size_read(jd->jd_inode) >> shift;
@@ -2280,6 +2283,10 @@ int gfs2_map_journal_extents(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
 		rc = gfs2_block_map(jd->jd_inode, lblock, &bh, 0);
 		if (rc || !buffer_mapped(&bh))
 			goto fail;
+		if (bh.b_blocknr << bshift > maxsector) {
+			rc = -EIO;
+			goto fail;
+		}
 		rc = gfs2_add_jextent(jd, lblock, bh.b_blocknr, bh.b_size >> shift);
 		if (rc)
 			goto fail;
-- 
2.43.0