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BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:185 [inline]
BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline]
BUG: KASAN: use-after-free in dbNextAG+0x2ff/0x370 fs/jfs/jfs_dmap.c:630
Read of size 4 at addr ffff8881bf92ee80 by task syz-executor176/8001

CPU: 1 PID: 8001 Comm: syz-executor176 Not tainted 4.14.294-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429
 __read_once_size include/linux/compiler.h:185 [inline]
 atomic_read arch/x86/include/asm/atomic.h:27 [inline]
 dbNextAG+0x2ff/0x370 fs/jfs/jfs_dmap.c:630
 diAlloc+0x87a/0x1230 fs/jfs/jfs_imap.c:1386
 ialloc+0x7b/0x940 fs/jfs/jfs_inode.c:70
 jfs_mkdir.part.0+0xfd/0x7e0 fs/jfs/namei.c:238
 jfs_mkdir+0x35/0x50 fs/jfs/namei.c:223
 vfs_mkdir+0x463/0x6e0 fs/namei.c:3851
 SYSC_mkdirat fs/namei.c:3874 [inline]
 SyS_mkdirat+0x1fd/0x270 fs/namei.c:3858
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f4965e24397
RSP: 002b:00007ffe5a546848 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffe5a5468f0 RCX: 00007f4965e24397
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 00000000200001c0
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000ffffffff R14: 00000000200001c0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006fe4b80 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x57ff00000000000()
raw: 057ff00000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: ffffea0006fe4ba0 ffffea0006fe4ba0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881bf92ed80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881bf92ee00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881bf92ee80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8881bf92ef00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881bf92ef80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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