jfs_dirty_inode called on read-only volume
Is remount racy?
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BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:72 [inline]
BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: null-ptr-deref in txBeginAnon+0x17b/0x3c0 fs/jfs/jfs_txnmgr.c:466
Read of size 8 at addr 0000000000000040 by task syz.3.4/4366

CPU: 1 PID: 4366 Comm: syz.3.4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 txBeginAnon+0x17b/0x3c0 fs/jfs/jfs_txnmgr.c:466
 extAlloc+0xed/0xf80 fs/jfs/jfs_extent.c:78
 jfs_get_block+0x355/0xad0 fs/jfs/inode.c:254
 get_more_blocks fs/direct-io.c:659 [inline]
 do_direct_IO fs/direct-io.c:947 [inline]
 __blockdev_direct_IO+0x1749/0x3570 fs/direct-io.c:1260
 blockdev_direct_IO include/linux/fs.h:3344 [inline]
 jfs_direct_IO+0x119/0x220 fs/jfs/inode.c:342
 generic_file_direct_write+0x10f/0x330 mm/filemap.c:3787
 __generic_file_write_iter+0x15f/0x2a0 mm/filemap.c:3945
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x642/0xb10 fs/read_write.c:861
 iter_file_splice_write+0x699/0xcc0 fs/splice.c:685
 do_splice_from fs/splice.c:763 [inline]
 direct_splice_actor+0xe1/0x130 fs/splice.c:950
 splice_direct_to_actor+0x48b/0xb90 fs/splice.c:896
 do_splice_direct+0x1ce/0x2f0 fs/splice.c:1002
 do_sendfile+0x5f3/0xea0 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1712d9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1713b8d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f1713015fa0 RCX: 00007f1712d9c819
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000006
RBP: 00007f1712e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe85 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1713016038 R14: 00007f1713015fa0 R15: 00007ffd4b91b3d8
 </TASK>
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