Re: [syzbot] [jfs?] KMSAN: uninit-value in txLock

syzbot
2026-04-17T18:49:02Z

KMSAN: uninit-value in txLock

ip: ffff8880139c57b8: 139c57b0 ffff8880 00000000 00000000
ip: ffff8880139c57c8: 00000000 00000000 00000000 00000000
ip: ffff8880139c57d8: 00000000 00000000
=====================================================
BUG: KMSAN: uninit-value in hex_dump_to_buffer+0xe86/0xeb0 lib/hexdump.c:172
hex_dump_to_buffer+0xe86/0xeb0 lib/hexdump.c:172
print_hex_dump+0x10d/0x330 lib/hexdump.c:277
txLock+0xe8f/0x29d0 fs/jfs/jfs_txnmgr.c:832
xtInsert+0xd25/0x1530 fs/jfs/jfs_xtree.c:645
extAlloc+0x12ec/0x17e0 fs/jfs/jfs_extent.c:150
jfs_get_block+0x610/0xe30 fs/jfs/inode.c:254
get_more_blocks fs/direct-io.c:648 [inline]
do_direct_IO fs/direct-io.c:936 [inline]
__blockdev_direct_IO+0x281f/0x6100 fs/direct-io.c:1243
blockdev_direct_IO include/linux/fs.h:3133 [inline]
jfs_direct_IO+0x12b/0x3f0 fs/jfs/inode.c:339
generic_file_direct_write+0x2bc/0x730 mm/filemap.c:4258
__generic_file_write_iter+0x25b/0x460 mm/filemap.c:4427
generic_file_write_iter+0x131/0x980 mm/filemap.c:4467
iter_file_splice_write+0x12d8/0x20c0 fs/splice.c:736
do_splice_from fs/splice.c:936 [inline]
direct_splice_actor+0x31a/0x7d0 fs/splice.c:1159
splice_direct_to_actor+0x9a3/0x1560 fs/splice.c:1103
do_splice_direct_actor fs/splice.c:1202 [inline]
do_splice_direct+0x1e0/0x350 fs/splice.c:1228
do_sendfile+0x9fc/0x1130 fs/read_write.c:1372
__do_sys_sendfile64 fs/read_write.c:1433 [inline]
__se_sys_sendfile64+0x1e3/0x280 fs/read_write.c:1419
__x64_sys_sendfile64+0xbd/0x120 fs/read_write.c:1419
x64_sys_call+0x3aa4/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
hex_dump_to_buffer+0xe7f/0xeb0 lib/hexdump.c:174
print_hex_dump+0x10d/0x330 lib/hexdump.c:277
txLock+0xe8f/0x29d0 fs/jfs/jfs_txnmgr.c:832
xtInsert+0xd25/0x1530 fs/jfs/jfs_xtree.c:645
extAlloc+0x12ec/0x17e0 fs/jfs/jfs_extent.c:150
jfs_get_block+0x610/0xe30 fs/jfs/inode.c:254
get_more_blocks fs/direct-io.c:648 [inline]
do_direct_IO fs/direct-io.c:936 [inline]
__blockdev_direct_IO+0x281f/0x6100 fs/direct-io.c:1243
blockdev_direct_IO include/linux/fs.h:3133 [inline]
jfs_direct_IO+0x12b/0x3f0 fs/jfs/inode.c:339
generic_file_direct_write+0x2bc/0x730 mm/filemap.c:4258
__generic_file_write_iter+0x25b/0x460 mm/filemap.c:4427
generic_file_write_iter+0x131/0x980 mm/filemap.c:4467
iter_file_splice_write+0x12d8/0x20c0 fs/splice.c:736
do_splice_from fs/splice.c:936 [inline]
direct_splice_actor+0x31a/0x7d0 fs/splice.c:1159
splice_direct_to_actor+0x9a3/0x1560 fs/splice.c:1103
do_splice_direct_actor fs/splice.c:1202 [inline]
do_splice_direct+0x1e0/0x350 fs/splice.c:1228
do_sendfile+0x9fc/0x1130 fs/read_write.c:1372
__do_sys_sendfile64 fs/read_write.c:1433 [inline]
__se_sys_sendfile64+0x1e3/0x280 fs/read_write.c:1419
__x64_sys_sendfile64+0xbd/0x120 fs/read_write.c:1419
x64_sys_call+0x3aa4/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
slab_post_alloc_hook mm/slub.c:4576 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
kmem_cache_alloc_noprof+0x373/0x1250 mm/slub.c:4905
mempool_alloc_slab+0x36/0x50 mm/mempool.c:722
mempool_alloc_noprof+0x19d/0x3c0 mm/mempool.c:566
alloc_metapage fs/jfs/jfs_metapage.c:264 [inline]
__get_metapage+0xa20/0x1840 fs/jfs/jfs_metapage.c:761
xtSplitRoot+0x164/0x1560 fs/jfs/jfs_xtree.c:1242
xtSplitUp+0x8c2/0x2ea0 fs/jfs/jfs_xtree.c:785
xtInsert+0x77a/0x1530 fs/jfs/jfs_xtree.c:608
extAlloc+0x12ec/0x17e0 fs/jfs/jfs_extent.c:150
jfs_get_block+0x610/0xe30 fs/jfs/inode.c:254
get_more_blocks fs/direct-io.c:648 [inline]
do_direct_IO fs/direct-io.c:936 [inline]
__blockdev_direct_IO+0x281f/0x6100 fs/direct-io.c:1243
blockdev_direct_IO include/linux/fs.h:3133 [inline]
jfs_direct_IO+0x12b/0x3f0 fs/jfs/inode.c:339
generic_file_direct_write+0x2bc/0x730 mm/filemap.c:4258
__generic_file_write_iter+0x25b/0x460 mm/filemap.c:4427
generic_file_write_iter+0x131/0x980 mm/filemap.c:4467
iter_file_splice_write+0x12d8/0x20c0 fs/splice.c:736
do_splice_from fs/splice.c:936 [inline]
direct_splice_actor+0x31a/0x7d0 fs/splice.c:1159
splice_direct_to_actor+0x9a3/0x1560 fs/splice.c:1103
do_splice_direct_actor fs/splice.c:1202 [inline]
do_splice_direct+0x1e0/0x350 fs/splice.c:1228
do_sendfile+0x9fc/0x1130 fs/read_write.c:1372
__do_sys_sendfile64 fs/read_write.c:1433 [inline]
__se_sys_sendfile64+0x1e3/0x280 fs/read_write.c:1419
__x64_sys_sendfile64+0xbd/0x120 fs/read_write.c:1419
x64_sys_call+0x3aa4/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 6587 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
=====================================================

Tested on:

commit: d662a710 Merge tag 'dmaengine-7.1-rc1' of git://git.ke..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14daa4ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5aa0042346eface8
dashboard link: https://syzkaller.appspot.com/bug?extid=d3a57c32b9112d7b01ec
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=171624ce580000