[syzbot] [jffs2?] KASAN: invalid-free in jffs2_free_inode
From: syzbot
Date: Sun Aug 23 2026 - 09:35:08 EST
Hello,
syzbot found the following issue on:
HEAD commit: b126f6f5940f Merge tag 'x86_mm_for_7.3-rc1' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ae2549580000
kernel config: https://syzkaller.appspot.com/x/.config?x=90b2fd087b14b23e
dashboard link: https://syzkaller.appspot.com/bug?extid=675e84fdf3dde67b4946
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=136c3a25580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-b126f6f5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c8d6c4cd1182/vmlinux-b126f6f5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/559693826b5b/bzImage-b126f6f5.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+675e84fdf3dde67b4946@xxxxxxxxxxxxxxxxxxxxxxxxx
R13: 00007f2c55825fac R14: 00007f2c55825fa0 R15: 00007f2c55825fa0
</TASK>
==================================================================
BUG: KASAN: double-free in jffs2_free_inode+0x39/0x60 fs/jffs2/super.c:52
Free of addr ffff8880371e2200 by task syz.0.345/6450
CPU: 0 UID: 0 PID: 6450 Comm: syz.0.345 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report_invalid_free+0xb8/0x190 mm/kasan/report.c:557
check_slab_allocation+0xc3/0xf0 mm/kasan/common.c:235
kasan_slab_pre_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:2622 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x1b6/0x6c0 mm/slub.c:6692
jffs2_free_inode+0x39/0x60 fs/jffs2/super.c:52
i_callback fs/inode.c:317 [inline]
alloc_inode+0x153/0x250 fs/inode.c:352
iget_locked+0x1d9/0x6d0 fs/inode.c:1473
jffs2_iget+0xb5/0xe30 fs/jffs2/fs.c:265
jffs2_lookup+0x353/0x410 fs/jffs2/dir.c:114
lookup_one_qstr_excl+0x1cd/0x250 fs/namei.c:1810
__start_dirop fs/namei.c:2920 [inline]
start_dirop fs/namei.c:2942 [inline]
filename_create+0x1cf/0x400 fs/namei.c:5092
filename_symlinkat+0xe1/0x560 fs/namei.c:5813
__do_sys_symlink fs/namei.c:5846 [inline]
__se_sys_symlink fs/namei.c:5842 [inline]
__x64_sys_symlink+0x79/0xb0 fs/namei.c:5842
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2c5559e0d9
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:00007ffc968200b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f2c55825fa0 RCX: 00007f2c5559e0d9
RDX: 0000000000000000 RSI: 0000200000000800 RDI: 0000200000000540
RBP: 00007ffc96820120 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f2c55825fac R14: 00007f2c55825fa0 R15: 00007f2c55825fa0
</TASK>
Allocated by task 6382:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kmalloc_noprof+0x324/0x820 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
_kmalloc_array_noprof include/linux/slab.h:1208 [inline]
security_inode_init_security+0x113/0x370 security/security.c:1347
shmem_symlink+0x163/0xa00 mm/shmem.c:4044
vfs_symlink fs/namei.c:5794 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5773
filename_symlinkat+0x2a6/0x560 fs/namei.c:5819
__do_sys_symlinkat fs/namei.c:5839 [inline]
__se_sys_symlinkat fs/namei.c:5834 [inline]
__x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6382:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6692
security_inode_init_security+0x2bf/0x370 security/security.c:1374
shmem_symlink+0x163/0xa00 mm/shmem.c:4044
vfs_symlink fs/namei.c:5794 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5773
filename_symlinkat+0x2a6/0x560 fs/namei.c:5819
__do_sys_symlinkat fs/namei.c:5839 [inline]
__se_sys_symlinkat fs/namei.c:5834 [inline]
__x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff8880371e2200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes inside of
256-byte region [ffff8880371e2200, ffff8880371e2300)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880371e2200 pfn:0x371e2
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801c042b40 ffffea0000e86f90 ffffea0000f41010
raw: ffff8880371e2200 000000080010000e 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801c042b40 ffffea0000e86f90 ffffea0000f41010
head: ffff8880371e2200 000000080010000e 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5784, tgid 5784 (syz-executor), ts 57239645098, free_ts 56961973186
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf46/0x3500 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x660 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x372/0x680 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x66b/0x820 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
_kmalloc_array_noprof include/linux/slab.h:1208 [inline]
security_inode_init_security+0x113/0x370 security/security.c:1347
shmem_mknod+0x2ce/0x480 mm/shmem.c:3814
shmem_mkdir+0x31/0x80 mm/shmem.c:3869
vfs_mkdir+0x364/0x850 fs/namei.c:5410
filename_mkdirat+0x48b/0x5e0 fs/namei.c:5443
__do_sys_mkdirat fs/namei.c:5464 [inline]
__se_sys_mkdirat fs/namei.c:5461 [inline]
__x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5461
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5777 tgid 5777 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4931
anon_vma_chain_alloc mm/rmap.c:142 [inline]
__anon_vma_prepare+0xae/0x5e0 mm/rmap.c:194
__vmf_anon_prepare+0x11f/0x250 mm/memory.c:3829
vmf_anon_prepare mm/internal.h:494 [inline]
do_anonymous_page+0x51b/0x2080 mm/memory.c:5338
do_pte_missing mm/memory.c:4564 [inline]
handle_pte_fault mm/memory.c:6379 [inline]
__handle_mm_fault+0x1d2c/0x2a00 mm/memory.c:6517
handle_mm_fault+0x37b/0xa30 mm/memory.c:6686
do_user_addr_fault+0x59c/0x12f0 arch/x86/mm/fault.c:1343
handle_page_fault arch/x86/mm/fault.c:1483 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1536
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
Memory state around the buggy address:
ffff8880371e2100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880371e2180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880371e2200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880371e2280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880371e2300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
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