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

[syzbot <syzbot+9013411dc43f3582823a@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in gfs2_invalidate_folio

RBP: 00007ffde9a1cf60 R08: 00007ffde9a1df60 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffde9a1dff0
R13: 00007fe90d032050 R14: 000000000001f130 R15: 00007ffde9a1e030
 </TASK>
gfs2: fsid=syz:syz.0: gfs2_evict_inode: -5
==================================================================
BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:381 [inline]
BUG: KASAN: slab-use-after-free in gfs2_discard fs/gfs2/aops.c:590 [inline]
BUG: KASAN: slab-use-after-free in gfs2_invalidate_folio+0x40b/0x750 fs/gfs2/aops.c:628
Read of size 8 at addr ffff88807c9098d8 by task syz-executor/6336

CPU: 0 UID: 0 PID: 6336 Comm: syz-executor 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
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 list_empty include/linux/list.h:381 [inline]
 gfs2_discard fs/gfs2/aops.c:590 [inline]
 gfs2_invalidate_folio+0x40b/0x750 fs/gfs2/aops.c:628
 folio_invalidate mm/truncate.c:140 [inline]
 truncate_cleanup_folio+0xcb/0x190 mm/truncate.c:160
 truncate_inode_pages_range+0x2ce/0xe30 mm/truncate.c:404
 gfs2_evict_inode+0x9da/0x12d0 fs/gfs2/super.c:1476
 evict+0x61e/0xb10 fs/inode.c:846
 gfs2_put_super+0x355/0x890 fs/gfs2/super.c:619
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe90cf9d9d7
Code: a2 c7 05 1c fd 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffde9a1cea8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fe90d032050 RCX: 00007fe90cf9d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffde9a1cf60
RBP: 00007ffde9a1cf60 R08: 00007ffde9a1df60 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffde9a1dff0
R13: 00007fe90d032050 R14: 000000000001f130 R15: 00007ffde9a1e030
 </TASK>

Allocated by task 6336:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905
 gfs2_alloc_bufdata fs/gfs2/trans.c:176 [inline]
 gfs2_trans_add_data+0x1e8/0x610 fs/gfs2/trans.c:215
 gfs2_unstuffer_folio fs/gfs2/bmap.c:81 [inline]
 __gfs2_unstuff_inode fs/gfs2/bmap.c:119 [inline]
 gfs2_unstuff_dinode+0xace/0x1240 fs/gfs2/bmap.c:166
 gfs2_adjust_quota+0x23f/0x850 fs/gfs2/quota.c:848
 do_sync+0x872/0xcb0 fs/gfs2/quota.c:962
 gfs2_quota_sync+0x370/0x470 fs/gfs2/quota.c:1358
 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:661
 sync_filesystem+0xee/0x230 fs/sync.c:56
 generic_shutdown_super+0x77/0x2d0 fs/super.c:625
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6336:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6242 [inline]
 kmem_cache_free+0x182/0x650 mm/slub.c:6369
 gfs2_trans_drain_list fs/gfs2/log.c:995 [inline]
 gfs2_trans_drain fs/gfs2/log.c:1013 [inline]
 gfs2_log_flush+0x18c1/0x2640 fs/gfs2/log.c:1185
 do_sync+0xa48/0xcb0 fs/gfs2/quota.c:982
 gfs2_quota_sync+0x370/0x470 fs/gfs2/quota.c:1358
 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:661
 sync_filesystem+0xee/0x230 fs/sync.c:56
 generic_shutdown_super+0x77/0x2d0 fs/super.c:625
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807c9098c0
 which belongs to the cache gfs2-bufdata/syz:syz of size 80
The buggy address is located 24 bytes inside of
 freed 80-byte region [ffff88807c9098c0, ffff88807c909910)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807c909a80 pfn:0x7c909
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff8881499c0500 ffff888035149d08 ffff888035149d08
raw: ffff88807c909a80 0000000800240018 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6336, tgid 6336 (syz-executor), ts 127950955156, free_ts 125551511102
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x2418/0x24b0 mm/page_alloc.c:3926
 __alloc_frozen_pages_noprof+0x233/0x3d0 mm/page_alloc.c:5213
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7247
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4905
 gfs2_alloc_bufdata fs/gfs2/trans.c:176 [inline]
 gfs2_trans_add_meta+0x214/0x8e0 fs/gfs2/trans.c:279
 gfs2_alloc_extent fs/gfs2/rgrp.c:2237 [inline]
 gfs2_alloc_blocks+0x7ae/0x2090 fs/gfs2/rgrp.c:2447
 __gfs2_unstuff_inode fs/gfs2/bmap.c:107 [inline]
 gfs2_unstuff_dinode+0x249/0x1240 fs/gfs2/bmap.c:166
 gfs2_adjust_quota+0x23f/0x850 fs/gfs2/quota.c:848
 do_sync+0x872/0xcb0 fs/gfs2/quota.c:962
 gfs2_quota_sync+0x370/0x470 fs/gfs2/quota.c:1358
 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:661
 sync_filesystem+0xee/0x230 fs/sync.c:56
 generic_shutdown_super+0x77/0x2d0 fs/super.c:625
page last free pid 23 tgid 23 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1403 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2944
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 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

Memory state around the buggy address:
 ffff88807c909780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807c909800: fc fc fc fc fc fc fc fc fc fc fa fb fb fb fb fb
>ffff88807c909880: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
                                                    ^
 ffff88807c909900: fb fb fc fc fc fc fa fb fb fb fb fb fb fb fb fb
 ffff88807c909980: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fc fc
==================================================================


Tested on:

commit:         85964cdc Add linux-next specific files for 20260324
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14e9506a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=84ab18c6f45b39c
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11b46a06580000