syzbot

blkno = 400000, nblocks = 0
ERROR: (device loop0): dbUpdatePMap.cold: blocks are outside the map
blkno = 400000, nblocks = 0
ERROR: (device loop0): dbFree: block to be freed is outside the map
==================================================================
BUG: KASAN: use-after-free in jfs_lazycommit+0x8d6/0x9d0 fs/jfs/jfs_txnmgr.c:2780
Read of size 4 at addr ffff8880a9ee48d4 by task jfsCommit/1984

CPU: 1 PID: 1984 Comm: jfsCommit Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
 jfs_lazycommit+0x8d6/0x9d0 fs/jfs/jfs_txnmgr.c:2780
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 8195:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 jfs_fill_super+0xaa/0xb50 fs/jfs/super.c:529
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x310 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2492 [inline]
 do_mount+0x115c/0x2f50 fs/namespace.c:2822
 ksys_mount+0xcf/0x130 fs/namespace.c:3038
 __do_sys_mount fs/namespace.c:3052 [inline]
 __se_sys_mount fs/namespace.c:3049 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3049
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8128:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 generic_shutdown_super+0x144/0x370 fs/super.c:456
 kill_block_super+0x97/0xf0 fs/super.c:1185
 deactivate_locked_super+0x94/0x160 fs/super.c:329
 deactivate_super+0x174/0x1a0 fs/super.c:360
 cleanup_mnt+0x1a8/0x290 fs/namespace.c:1098
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a9ee4840
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 148 bytes inside of
 256-byte region [ffff8880a9ee4840, ffff8880a9ee4940)
The buggy address belongs to the page:
page:ffffea0002a7b900 count:1 mapcount:0 mapping:ffff88813bff07c0 index:0x0
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea0002a07fc8 ffffea0002a79bc8 ffff88813bff07c0
raw: 0000000000000000 ffff8880a9ee40c0 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9ee4780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a9ee4800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880a9ee4880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8880a9ee4900: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880a9ee4980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================