[syzbot] [jffs2?] KASAN: slab-out-of-bounds Read in jffs2_sum_add_kvec

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 707081b61156 Merge branch 'for-next/core', remote-tracking..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1100ac99180000
kernel config: https://syzkaller.appspot.com/x/.config?x=caeac3f3565b057a
dashboard link: https://syzkaller.appspot.com/bug?extid=d7c218ea1def103f6bcd
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=149f31f6180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15f2c5a1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6cad68bf7532/disk-707081b6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1a27e5400778/vmlinux-707081b6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/67dfc53755d0/Image-707081b6.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d7c218...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in jffs2_sum_add_kvec+0x99c/0x11e4 fs/jffs2/summary.c:261
Read of size 4 at addr ffff0000d8ccacbc by task jffs2_gcd_mtd0/6173

CPU: 1 PID: 6173 Comm: jffs2_gcd_mtd0 Not tainted 6.8.0-rc7-syzkaller-g707081b61156 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x178/0x518 mm/kasan/report.c:488
kasan_report+0xd8/0x138 mm/kasan/report.c:601
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
jffs2_sum_add_kvec+0x99c/0x11e4 fs/jffs2/summary.c:261
jffs2_flash_direct_writev+0xa8/0xe8 fs/jffs2/writev.c:22
jffs2_flash_writev+0x13c/0x11ac fs/jffs2/wbuf.c:805
jffs2_write_dnode+0x3cc/0xb80 fs/jffs2/write.c:109
jffs2_garbage_collect_metadata fs/jffs2/gc.c:834 [inline]
jffs2_garbage_collect_live+0x1098/0x3640 fs/jffs2/gc.c:529
jffs2_garbage_collect_pass+0x1470/0x1a50 fs/jffs2/gc.c:464
jffs2_garbage_collect_thread+0x414/0x48c fs/jffs2/background.c:155
kthread+0x288/0x310 kernel/kthread.c:388
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

Allocated by task 6162:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:575
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slub.c:3981 [inline]
__kmalloc+0x2bc/0x5d4 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]
kzalloc include/linux/slab.h:711 [inline]
jffs2_do_mount_fs+0x120/0x1d00 fs/jffs2/build.c:387
jffs2_do_fill_super+0x480/0x9f8 fs/jffs2/fs.c:573
jffs2_fill_super+0x248/0x280 fs/jffs2/super.c:289
mtd_get_sb+0x174/0x398 drivers/mtd/mtdsuper.c:57
mtd_get_sb_by_nr+0x94/0xb0 drivers/mtd/mtdsuper.c:88
get_tree_mtd+0x4e4/0x680 drivers/mtd/mtdsuper.c:141
jffs2_get_tree+0x28/0x38 fs/jffs2/super.c:294
vfs_get_tree+0x90/0x288 fs/super.c:1779
do_new_mount+0x278/0x900 fs/namespace.c:3352
path_mount+0x590/0xe04 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3875
__invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

The buggy address belongs to the object at ffff0000d8cca000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 956 bytes to the right of
allocated 2304-byte region [ffff0000d8cca000, ffff0000d8cca900)

The buggy address belongs to the physical page:
page:00000000c4bc55ea refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x118cc8
head:00000000c4bc55ea order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x5ffc00000000840(slab|head|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000840 ffff0000c0002140 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000d8ccab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000d8ccac00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d8ccac80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff0000d8ccad00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000d8ccad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
jffs2: Write of 68 bytes at 0x0002d034 failed. returned -22, retlen 0
jffs2: Not marking the space at 0x0002d034 as dirty because the flash driver returned retlen zero
jffs2: error: (6173) __jffs2_dbg_acct_sanity_check_nolock: eeep, space accounting for block at 0x00000000 is screwed.
jffs2: error: (6173) __jffs2_dbg_acct_sanity_check_nolock: free 0x000000 + dirty 0x000000 + used 0x000000 + wasted 0x000000 + unchecked 0x000000 != total 0x001000.
------------[ cut here ]------------
kernel BUG at fs/jffs2/debug.c:38!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 6173 Comm: jffs2_gcd_mtd0 Tainted: G B 6.8.0-rc7-syzkaller-g707081b61156 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __jffs2_dbg_acct_sanity_check_nolock+0x57c/0x76c fs/jffs2/debug.c:35
lr : __jffs2_dbg_acct_sanity_check_nolock+0x57c/0x76c fs/jffs2/debug.c:35
sp : ffff800097947440
x29: ffff8000979474b0 x28: ffff0000d8ccaccc x27: 0000000000000000
x26: 0000000000000000 x25: 0000000000000000 x24: ffff0000d8f68180
x23: 0000000000000000 x22: 0000000000000000 x21: ffff0000d8ccacc4
x20: dfff800000000000 x19: 000000000000181d x18: 1fffe00036804396
x17: 0000000000000000 x16: ffff80008aca6b80 x15: 0000000000000001
x14: 1ffff00012f28da8 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000002 x10: 0000000000ff0100 x9 : a157a05fb2900e00
x8 : a157a05fb2900e00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff800097946d58 x4 : ffff80008ed822c0 x3 : ffff80008036f0d8
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 00000000000000a3
Call trace:
__jffs2_dbg_acct_sanity_check_nolock+0x57c/0x76c fs/jffs2/debug.c:35
__jffs2_dbg_acct_sanity_check+0x38/0x54 fs/jffs2/debug.c:56
jffs2_write_dnode+0x4ec/0xb80 fs/jffs2/write.c:137
jffs2_garbage_collect_metadata fs/jffs2/gc.c:834 [inline]
jffs2_garbage_collect_live+0x1098/0x3640 fs/jffs2/gc.c:529
jffs2_garbage_collect_pass+0x1470/0x1a50 fs/jffs2/gc.c:464
jffs2_garbage_collect_thread+0x414/0x48c fs/jffs2/background.c:155
kthread+0x288/0x310 kernel/kthread.c:388
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860
Code: 2a1703e6 2a1603e7 b90003e8 959b3174 (d4210000)
---[ end trace 0000000000000000 ]---


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