[syzbot] [jffs2?] [nilfs?] KASAN: slab-use-after-free Read in jffs2_garbage_collect_pass

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Apr 5, 2024, 6:01:32ā€ÆAMApr 5
to dw...@infradead.org, konishi...@gmail.com, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@lists.infradead.org, linux...@vger.kernel.org, ric...@nod.at, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ea8b3d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=e84662c5f30b8c401437
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=141bc615180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=148423e3180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/72ab73815344/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d6d6b0d7071/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48e275e5478b/bzImage-fe46a7dd.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a3126c30eb43/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e84662...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline]
BUG: KASAN: slab-use-after-free in __mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
Read of size 8 at addr ffff88807e402130 by task jffs2_gcd_mtd0/5063

CPU: 0 PID: 5063 Comm: jffs2_gcd_mtd0 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
__mutex_lock_common kernel/locking/mutex.c:587 [inline]
__mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
jffs2_garbage_collect_pass+0xae/0x2120 fs/jffs2/gc.c:134
jffs2_garbage_collect_thread+0x651/0x6e0 fs/jffs2/background.c:155
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>

Allocated by task 5052:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace+0x1db/0x360 mm/slub.c:3997
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
jffs2_init_fs_context+0x4f/0xc0 fs/jffs2/super.c:313
alloc_fs_context+0x68a/0x800 fs/fs_context.c:318
do_new_mount+0x160/0xb40 fs/namespace.c:3331
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Freed by task 5052:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2106 [inline]
slab_free mm/slub.c:4280 [inline]
kfree+0x14a/0x380 mm/slub.c:4390
deactivate_locked_super+0xc4/0x130 fs/super.c:472
cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

The buggy address belongs to the object at ffff88807e402000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 304 bytes inside of
freed 4096-byte region [ffff88807e402000, ffff88807e403000)

The buggy address belongs to the physical page:
page:ffffea0001f90000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e400
head:ffffea0001f90000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888014c42140 ffffea0000937e00 0000000000000002
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4727, tgid 4727 (dhcpcd), ts 35281916523, free_ts 35270327271
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
__alloc_pages+0x256/0x680 mm/page_alloc.c:4569
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
__do_kmalloc_node mm/slub.c:3965 [inline]
__kmalloc+0x2e5/0x4a0 mm/slub.c:3979
kmalloc include/linux/slab.h:632 [inline]
tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x255/0x500 security/tomoyo/file.c:771
security_file_open+0x69/0x570 security/security.c:2955
do_dentry_open+0x327/0x15a0 fs/open.c:942
do_open fs/namei.c:3642 [inline]
path_openat+0x2860/0x3240 fs/namei.c:3799
do_filp_open+0x235/0x490 fs/namei.c:3826
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
do_syscall_64+0xfb/0x240
page last free pid 4727 tgid 4727 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x95d/0xa80 mm/page_alloc.c:2346
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
discard_slab mm/slub.c:2437 [inline]
__put_partials+0xeb/0x130 mm/slub.c:2906
put_cpu_partial+0x17c/0x250 mm/slub.c:2981
__slab_free+0x2ea/0x3d0 mm/slub.c:4151
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc+0x174/0x340 mm/slub.c:3852
getname_flags+0xbd/0x4f0 fs/namei.c:139
vfs_fstatat+0x11c/0x190 fs/stat.c:303
__do_sys_newfstatat fs/stat.c:468 [inline]
__se_sys_newfstatat fs/stat.c:462 [inline]
__x64_sys_newfstatat+0x117/0x190 fs/stat.c:462
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Memory state around the buggy address:
ffff88807e402000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807e402080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807e402100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807e402180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807e402200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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syzbot

unread,
Apr 5, 2024, 8:01:06ā€ÆAMApr 5
to ar...@arndb.de, dhow...@redhat.com, dw...@infradead.org, konishi...@gmail.com, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@lists.infradead.org, linux...@vger.kernel.org, ric...@nod.at, syzkall...@googlegroups.com, vi...@zeniv.linux.org.uk
syzbot has bisected this issue to:

commit 9c8ad7a2ff0bfe58f019ec0abc1fb965114dde7d
Author: David Howells <dhow...@redhat.com>
Date: Thu May 16 11:52:27 2019 +0000

uapi, x86: Fix the syscall numbering of the mount API syscalls [ver #2]

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=113c6b3d180000
start commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=133c6b3d180000
console output: https://syzkaller.appspot.com/x/log.txt?x=153c6b3d180000
Reported-by: syzbot+e84662...@syzkaller.appspotmail.com
Fixes: 9c8ad7a2ff0b ("uapi, x86: Fix the syscall numbering of the mount API syscalls [ver #2]")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Jeongjun Park

unread,
Apr 22, 2024, 1:10:32ā€ÆAMĀ (8 days ago)Ā Apr 22
to syzbot+e84662...@syzkaller.appspotmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
please test slab-use-after-free Read in jffs2_garbage_collect_pass

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

syzbot

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Apr 22, 2024, 1:23:05ā€ÆAMĀ (8 days ago)Ā Apr 22
to aha3...@gmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in jffs2_garbage_collect_pass

==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline]
BUG: KASAN: slab-use-after-free in __mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
Read of size 8 at addr ffff888061ba6130 by task jffs2_gcd_mtd0/5501

CPU: 0 PID: 5501 Comm: jffs2_gcd_mtd0 Not tainted 6.9.0-rc5-syzkaller-ged30a4a51bb1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
__mutex_lock_common kernel/locking/mutex.c:587 [inline]
__mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
jffs2_garbage_collect_pass+0xae/0x2120 fs/jffs2/gc.c:134
jffs2_garbage_collect_thread+0x651/0x6e0 fs/jffs2/background.c:155
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 5495:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace+0x1db/0x360 mm/slub.c:3997
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
jffs2_init_fs_context+0x4f/0xc0 fs/jffs2/super.c:313
alloc_fs_context+0x68a/0x800 fs/fs_context.c:318
do_new_mount+0x160/0xb40 fs/namespace.c:3331
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5428:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2106 [inline]
slab_free mm/slub.c:4280 [inline]
kfree+0x153/0x3a0 mm/slub.c:4390
deactivate_locked_super+0xc4/0x130 fs/super.c:472
cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
task_work_run+0x24f/0x310 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888061ba6000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 304 bytes inside of
freed 4096-byte region [ffff888061ba6000, ffff888061ba7000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61ba0
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff888015042140 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
head: 00fff80000000840 ffff888015042140 dead000000000122 0000000000000000
head: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
head: 00fff80000000003 ffffea000186e801 dead000000000122 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5494, tgid -833224093 (syz-executor.0), ts 5495, free_ts 89333775363
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
__alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
__do_kmalloc_node mm/slub.c:3965 [inline]
__kmalloc+0x2e5/0x4a0 mm/slub.c:3979
kmalloc include/linux/slab.h:632 [inline]
tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x255/0x500 security/tomoyo/file.c:771
security_file_open+0x69/0x570 security/security.c:2961
do_dentry_open+0x327/0x15a0 fs/open.c:942
do_open fs/namei.c:3642 [inline]
path_openat+0x2860/0x3240 fs/namei.c:3799
do_filp_open+0x235/0x490 fs/namei.c:3826
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
page last free pid 5445 tgid 5445 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1141 [inline]
free_unref_page_prepare+0x97b/0xaa0 mm/page_alloc.c:2347
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
__slab_free+0x31b/0x3d0 mm/slub.c:4192
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc+0x174/0x340 mm/slub.c:3852
getname_flags+0xbd/0x4f0 fs/namei.c:139
getname fs/namei.c:218 [inline]
__do_sys_rename fs/namei.c:5084 [inline]
__se_sys_rename fs/namei.c:5082 [inline]
__x64_sys_rename+0x5f/0xa0 fs/namei.c:5082
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888061ba6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888061ba6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888061ba6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888061ba6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888061ba6200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: ed30a4a5 Linux 6.9-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=133bb3ab180000
kernel config: https://syzkaller.appspot.com/x/.config?x=ab247b9c410b3012
dashboard link: https://syzkaller.appspot.com/bug?extid=e84662c5f30b8c401437
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Jeongjun Park

unread,
Apr 22, 2024, 1:29:17ā€ÆAMĀ (8 days ago)Ā Apr 22
to syzbot+e84662...@syzkaller.appspotmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
please test slab-use-after-free Read in jffs2_garbage_collect_pass

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
fs/jffs2/super.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index aede1be4dc0c..49bf8e11c11c 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -348,6 +348,7 @@ static void jffs2_kill_sb(struct super_block *sb)
jffs2_stop_garbage_collect_thread(c);
kill_mtd_super(sb);
kfree(c);
+ memset(&c, 0, sizeof(struct jffs2_sb_info));
}

static struct file_system_type jffs2_fs_type = {
--
2.34.1

syzbot

unread,
Apr 22, 2024, 1:46:05ā€ÆAMĀ (8 days ago)Ā Apr 22
to aha3...@gmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in jffs2_garbage_collect_pass

==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline]
BUG: KASAN: slab-use-after-free in __mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
Read of size 8 at addr ffff88802f3a8130 by task jffs2_gcd_mtd0/5495

CPU: 0 PID: 5495 Comm: jffs2_gcd_mtd0 Not tainted 6.9.0-rc5-syzkaller-ged30a4a51bb1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
__mutex_lock_common kernel/locking/mutex.c:587 [inline]
__mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752
jffs2_garbage_collect_pass+0xae/0x2120 fs/jffs2/gc.c:134
jffs2_garbage_collect_thread+0x651/0x6e0 fs/jffs2/background.c:155
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 5492:
The buggy address belongs to the object at ffff88802f3a8000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 304 bytes inside of
freed 4096-byte region [ffff88802f3a8000, ffff88802f3a9000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2f3a8
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff888015042140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
head: 00fff80000000840 ffff888015042140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
head: 00fff80000000003 ffffea0000bcea01 ffffea0000bcea48 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4825, tgid 890569257 (dhcpcd), ts 4825, free_ts 35233298414
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
__alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmalloc_trace+0x269/0x360 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
tomoyo_find_next_domain+0x15b/0x1cf0 security/tomoyo/domain.c:714
tomoyo_bprm_check_security+0x115/0x180 security/tomoyo/tomoyo.c:102
security_bprm_check+0x65/0x90 security/security.c:1191
search_binary_handler fs/exec.c:1766 [inline]
exec_binprm fs/exec.c:1820 [inline]
bprm_execve+0xa56/0x17c0 fs/exec.c:1872
do_execveat_common+0x553/0x700 fs/exec.c:1979
do_execve fs/exec.c:2053 [inline]
__do_sys_execve fs/exec.c:2129 [inline]
__se_sys_execve fs/exec.c:2124 [inline]
__x64_sys_execve+0x92/0xb0 fs/exec.c:2124
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4743 tgid 4743 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1141 [inline]
free_unref_page_prepare+0x97b/0xaa0 mm/page_alloc.c:2347
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
discard_slab mm/slub.c:2437 [inline]
__put_partials+0xeb/0x130 mm/slub.c:2906
put_cpu_partial+0x17c/0x250 mm/slub.c:2981
__slab_free+0x2ea/0x3d0 mm/slub.c:4151
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc_node+0x194/0x380 mm/slub.c:3888
__alloc_skb+0x1c3/0x440 net/core/skbuff.c:658
alloc_skb include/linux/skbuff.h:1313 [inline]
nlmsg_new include/net/netlink.h:1010 [inline]
netlink_ack+0x399/0x12b0 net/netlink/af_netlink.c:2496
netlink_rcv_skb+0x262/0x430 net/netlink/af_netlink.c:2565
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1217
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745

Memory state around the buggy address:
ffff88802f3a8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802f3a8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802f3a8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802f3a8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802f3a8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: ed30a4a5 Linux 6.9-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11efdc80980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ab247b9c410b3012
dashboard link: https://syzkaller.appspot.com/bug?extid=e84662c5f30b8c401437
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=14d3fb1b180000

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