================================================================== BUG: KASAN: slab-use-after-free in txEnd+0xe8/0x4f0 fs/jfs/jfs_txnmgr.c:507 Read of size 8 at addr ffff0000cfb3fc30 by task jfsCommit/100 CPU: 0 UID: 0 PID: 100 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xa8/0x238 mm/kasan/report.c:378 print_report+0x68/0x84 mm/kasan/report.c:482 kasan_report+0xb0/0x110 mm/kasan/report.c:595 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 txEnd+0xe8/0x4f0 fs/jfs/jfs_txnmgr.c:507 txLazyCommit fs/jfs/jfs_txnmgr.c:2685 [inline] jfs_lazycommit+0x4b4/0x94c fs/jfs/jfs_txnmgr.c:2734 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 Allocated by task 10138: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:570 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3b8/0x698 mm/slub.c:5776 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] jfs_fill_super+0xb8/0xb6c fs/jfs/super.c:452 get_tree_bdev_flags+0x360/0x414 fs/super.c:1691 get_tree_bdev+0x2c/0x3c fs/super.c:1714 jfs_get_tree+0x28/0x38 fs/jfs/super.c:635 vfs_get_tree+0x90/0x28c fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x284/0x944 fs/namespace.c:3712 path_mount+0x5b4/0xdfc fs/namespace.c:4022 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount fs/namespace.c:4201 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4201 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Freed by task 6721: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x1c4/0x5fc mm/slub.c:6878 jfs_put_super+0x144/0x188 fs/jfs/super.c:203 generic_shutdown_super+0x12c/0x2b8 fs/super.c:643 kill_block_super+0x44/0x90 fs/super.c:1722 deactivate_locked_super+0xc4/0x12c fs/super.c:474 deactivate_super+0xe0/0x100 fs/super.c:507 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1318 __cleanup_mnt+0x20/0x30 fs/namespace.c:1325 task_work_run+0x1dc/0x260 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:44 [inline] exit_to_user_mode_loop+0x10c/0x18c kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] exit_to_user_mode_prepare_legacy include/linux/irq-entry-common.h:242 [inline] arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:81 [inline] el0_svc+0x17c/0x26c arch/arm64/kernel/entry-common.c:725 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 The buggy address belongs to the object at ffff0000cfb3fc00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff0000cfb3fc00, ffff0000cfb3fd00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10fb3e head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0001b40 fffffdffc37a8f80 dead000000000005 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0001b40 fffffdffc37a8f80 dead000000000005 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 05ffc00000000001 fffffdffc33ecf81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000cfb3fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000cfb3fb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000cfb3fc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000cfb3fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000cfb3fd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Unable to handle kernel paging request at virtual address dfff800000000029 KASAN: null-ptr-deref in range [0x0000000000000148-0x000000000000014f] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff800000000029] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] SMP Modules linked in: CPU: 0 UID: 0 PID: 100 Comm: jfsCommit Tainted: G B syzkaller #0 PREEMPT Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : txEnd+0x180/0x4f0 fs/jfs/jfs_txnmgr.c:540 lr : txEnd+0x158/0x4f0 fs/jfs/jfs_txnmgr.c:529 sp : ffff800099ab7c60 x29: ffff800099ab7c60 x28: 1ffff00013357288 x27: ffff80008fe93000 x26: 1ffff00011fd27a0 x25: dfff800000000000 x24: ffff80009773f000 x23: 0000000000000007 x22: 000000000000014c x21: ffff800099ab9468 x20: 0000000000000004 x19: 0000000000000000 x18: 1fffe0003377d090 x17: 3d3d3d3d3d3d3d3d x16: ffff800082e5e68c x15: 0000000000000001 x14: 1ffff0001261fd18 x13: 0000000000000000 x12: 0000000000000000 x11: ffff70001261fd19 x10: 0000000000ff0100 x9 : 0000000000000029 x8 : 0000000000000004 x7 : 0000000000000001 x6 : ffff8000805761f8 x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000803c8c30 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: txEnd+0x180/0x4f0 fs/jfs/jfs_txnmgr.c:535 (P) txLazyCommit fs/jfs/jfs_txnmgr.c:2685 [inline] jfs_lazycommit+0x4b4/0x94c fs/jfs/jfs_txnmgr.c:2734 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 Code: 12003e88 790002b7 d343fec9 b9040308 (38f96928) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 12003e88 and w8, w20, #0xffff 4: 790002b7 strh w23, [x21] 8: d343fec9 lsr x9, x22, #3 c: b9040308 str w8, [x24, #1024] * 10: 38f96928 ldrsb w8, [x9, x25] <-- trapping instruction