KASAN: use-after-free Read in f2fs_write_end_io

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 200e340f2196 Merge tag 'pull-work.dcache' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1184fa3e080000
kernel config: https://syzkaller.appspot.com/x/.config?x=a3f4d6985d3164cd
dashboard link: https://syzkaller.appspot.com/bug?extid=bc791e0778a6a5616c33
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386
CC: [ch...@kernel.org jae...@kernel.org linux-f2...@lists.sourceforge.net linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bc791e...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in get_pages fs/f2fs/f2fs.h:2423 [inline]
BUG: KASAN: use-after-free in f2fs_write_end_io+0x141/0x12a0 fs/f2fs/data.c:348
Read of size 4 at addr ffff8880752b4e58 by task ksoftirqd/1/23

CPU: 1 PID: 23 Comm: ksoftirqd/1 Not tainted 5.19.0-syzkaller-02972-g200e340f2196 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read include/linux/instrumented.h:71 [inline]
atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
get_pages fs/f2fs/f2fs.h:2423 [inline]
f2fs_write_end_io+0x141/0x12a0 fs/f2fs/data.c:348
bio_endio+0x5fe/0x780 block/bio.c:1562
req_bio_endio block/blk-mq.c:695 [inline]
blk_update_request+0x401/0x1310 block/blk-mq.c:825
blk_mq_end_request+0x4b/0x80 block/blk-mq.c:951
blk_flush_complete_seq+0x561/0xfd0 block/blk-flush.c:211
flush_end_io+0x77a/0xc60 block/blk-flush.c:268
__blk_mq_end_request+0x123/0x580 block/blk-mq.c:942
lo_complete_rq+0x1c2/0x280 drivers/block/loop.c:370
blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022
__do_softirq+0x29b/0x9c2 kernel/softirq.c:571
run_ksoftirqd kernel/softirq.c:934 [inline]
run_ksoftirqd+0x2d/0x60 kernel/softirq.c:926
smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164
kthread+0x2e9/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Allocated by task 16300:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:437 [inline]
____kasan_kmalloc mm/kasan/common.c:516 [inline]
____kasan_kmalloc mm/kasan/common.c:475 [inline]
__kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
f2fs_fill_super+0xf9/0x75d0 fs/f2fs/super.c:3999
mount_bdev+0x34d/0x410 fs/super.c:1367
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1497
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x1320/0x1fa0 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__ia32_sys_mount+0x27e/0x300 fs/namespace.c:3568
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
entry_SYSENTER_compat_after_hwframe+0x70/0x82

Freed by task 3896:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:367 [inline]
____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:329
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1754 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
slab_free mm/slub.c:3534 [inline]
kfree+0xe2/0x4d0 mm/slub.c:4562
f2fs_put_super+0x7d4/0xc10 fs/f2fs/super.c:1603
generic_shutdown_super+0x14c/0x400 fs/super.c:462
kill_block_super+0x97/0xf0 fs/super.c:1394
kill_f2fs_super+0x2b3/0x3c0 fs/f2fs/super.c:4516
deactivate_locked_super+0x94/0x160 fs/super.c:332
deactivate_super+0xad/0xd0 fs/super.c:363
cleanup_mnt+0x3a2/0x540 fs/namespace.c:1186
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
__do_fast_syscall_32+0x72/0xf0 arch/x86/entry/common.c:181
do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
entry_SYSENTER_compat_after_hwframe+0x70/0x82

The buggy address belongs to the object at ffff8880752b4000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3672 bytes inside of
8192-byte region [ffff8880752b4000, ffff8880752b6000)

The buggy address belongs to the physical page:
page:ffffea0001d4ac00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x752b0
head:ffffea0001d4ac00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4fff00000010200(slab|head|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000010200 ffffea0000864200 dead000000000002 ffff888011843180
raw: 0000000000000000 0000000080020002 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 15655, tgid 15654 (syz-executor.0), ts 723661245241, free_ts 723629165352
prep_new_page mm/page_alloc.c:2457 [inline]
get_page_from_freelist+0x1298/0x3b80 mm/page_alloc.c:4203
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5431
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272
alloc_slab_page mm/slub.c:1824 [inline]
allocate_slab+0x26c/0x3c0 mm/slub.c:1969
new_slab mm/slub.c:2029 [inline]
___slab_alloc+0x99f/0xe10 mm/slub.c:3031
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
slab_alloc_node mm/slub.c:3209 [inline]
slab_alloc mm/slub.c:3251 [inline]
__kmalloc_track_caller+0x36f/0x450 mm/slub.c:4924
copy_array+0xc5/0xe0 kernel/bpf/verifier.c:991
copy_stack_state kernel/bpf/verifier.c:1037 [inline]
copy_func_state kernel/bpf/verifier.c:1154 [inline]
copy_verifier_state+0x71e/0xb80 kernel/bpf/verifier.c:1190
is_state_visited kernel/bpf/verifier.c:11876 [inline]
do_check kernel/bpf/verifier.c:11991 [inline]
do_check_common+0x19f5/0xd010 kernel/bpf/verifier.c:14371
do_check_main kernel/bpf/verifier.c:14434 [inline]
bpf_check+0x8538/0xb680 kernel/bpf/verifier.c:15003
bpf_prog_load+0xfb2/0x2250 kernel/bpf/syscall.c:2575
__sys_bpf+0x11a1/0x5700 kernel/bpf/syscall.c:4917
__do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
__ia32_sys_bpf+0x74/0xc0 kernel/bpf/syscall.c:5019
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1371 [inline]
free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1421
free_unref_page_prepare mm/page_alloc.c:3344 [inline]
free_unref_page+0x19/0x6a0 mm/page_alloc.c:3439
__unfreeze_partials+0x17c/0x1a0 mm/slub.c:2548
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:727 [inline]
slab_alloc_node mm/slub.c:3243 [inline]
slab_alloc mm/slub.c:3251 [inline]
kmem_cache_alloc_trace+0x271/0x3f0 mm/slub.c:3282
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
kernfs_fop_open+0x317/0xda0 fs/kernfs/file.c:621
do_dentry_open+0x4a1/0x12d0 fs/open.c:878
do_open fs/namei.c:3499 [inline]
path_openat+0x1c92/0x28f0 fs/namei.c:3632
do_filp_open+0x1b6/0x400 fs/namei.c:3659
do_sys_openat2+0x16d/0x4c0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1337
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff8880752b4d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880752b4d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880752b4e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880752b4e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880752b4f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[Dmitry Vyukov]

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