Re: [syzbot] KASAN: use-after-free Read in disk_part_iter_next (2)

From: syzbot
Date: Sat Mar 20 2021 - 17:03:56 EST

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syzbot has found a reproducer for the following issue on:

HEAD commit: 1c273e10 Merge tag 'zonefs-5.12-rc4' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16889906d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6abda3336c698a07
dashboard link: https://syzkaller.appspot.com/bug?extid=8fede7e30c7cee0de139
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13dfe8bed00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155a117cd00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8fede7e30c7cee0de139@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in bdev_nr_sectors include/linux/genhd.h:266 [inline]
BUG: KASAN: use-after-free in disk_part_iter_next+0x49d/0x530 block/genhd.c:206
Read of size 8 at addr ffff88803268d0a8 by task syz-executor193/10255

CPU: 0 PID: 10255 Comm: syz-executor193 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
__kasan_report mm/kasan/report.c:399 [inline]
kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
bdev_nr_sectors include/linux/genhd.h:266 [inline]
disk_part_iter_next+0x49d/0x530 block/genhd.c:206
partition_overlaps+0x96/0x200 block/partitions/core.c:425
bdev_add_partition+0x66/0x130 block/partitions/core.c:444
blkpg_do_ioctl+0x2d0/0x340 block/ioctl.c:43
blkpg_ioctl block/ioctl.c:60 [inline]
blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548
block_ioctl+0xf9/0x140 fs/block_dev.c:1667
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445739
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffca5947308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000445739
RDX: 0000000020000240 RSI: 0000000000001269 RDI: 0000000000000003
RBP: 00007ffca5947380 R08: 000000000000ece4 R09: 000000000000ece4
R10: 0023706f6f6c2f76 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffca5947370 R14: 00007ffca5947360 R15: 00007ffca594732c

Allocated by task 10192:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:427 [inline]
__kasan_slab_alloc+0x75/0x90 mm/kasan/common.c:460
kasan_slab_alloc include/linux/kasan.h:223 [inline]
slab_post_alloc_hook mm/slab.h:516 [inline]
slab_alloc_node mm/slub.c:2907 [inline]
slab_alloc mm/slub.c:2915 [inline]
kmem_cache_alloc+0x155/0x370 mm/slub.c:2920
bdev_alloc_inode+0x18/0x80 fs/block_dev.c:795
alloc_inode+0x61/0x230 fs/inode.c:234
new_inode_pseudo fs/inode.c:928 [inline]
new_inode+0x27/0x2f0 fs/inode.c:957
bdev_alloc+0x20/0x2f0 fs/block_dev.c:885
add_partition+0x1ab/0x880 block/partitions/core.c:346
bdev_add_partition+0xb6/0x130 block/partitions/core.c:449
blkpg_do_ioctl+0x2d0/0x340 block/ioctl.c:43
blkpg_ioctl block/ioctl.c:60 [inline]
blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548
block_ioctl+0xf9/0x140 fs/block_dev.c:1667
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 0:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
____kasan_slab_free mm/kasan/common.c:360 [inline]
____kasan_slab_free mm/kasan/common.c:325 [inline]
__kasan_slab_free+0xf5/0x130 mm/kasan/common.c:367
kasan_slab_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:1562 [inline]
slab_free_freelist_hook+0x92/0x210 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kmem_cache_free+0x8a/0x740 mm/slub.c:3177
i_callback+0x3f/0x70 fs/inode.c:223
rcu_do_batch kernel/rcu/tree.c:2559 [inline]
rcu_core+0x74a/0x12f0 kernel/rcu/tree.c:2794
__do_softirq+0x29b/0x9f6 kernel/softirq.c:345

Last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345
__call_rcu kernel/rcu/tree.c:3039 [inline]
call_rcu+0xb1/0x740 kernel/rcu/tree.c:3114
destroy_inode+0x129/0x1b0 fs/inode.c:289
iput_final fs/inode.c:1654 [inline]
iput.part.0+0x57e/0x810 fs/inode.c:1680
iput+0x58/0x70 fs/inode.c:1670
disk_part_iter_exit block/genhd.c:235 [inline]
disk_part_iter_next+0x9a/0x530 block/genhd.c:202
blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541
bdev_disk_changed+0x238/0x430 fs/block_dev.c:1246
__loop_clr_fd+0x7c7/0xff0 drivers/block/loop.c:1271
lo_release+0x1ac/0x1f0 drivers/block/loop.c:1923
__blkdev_put+0x54e/0x800 fs/block_dev.c:1588
blkdev_put+0x92/0x580 fs/block_dev.c:1641
blkdev_close+0x8c/0xb0 fs/block_dev.c:1649
__fput+0x288/0x920 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:140
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208
__syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x44/0xae

Second to last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345
__call_rcu kernel/rcu/tree.c:3039 [inline]
call_rcu+0xb1/0x740 kernel/rcu/tree.c:3114
destroy_inode+0x129/0x1b0 fs/inode.c:289
iput_final fs/inode.c:1654 [inline]
iput.part.0+0x57e/0x810 fs/inode.c:1680
iput+0x58/0x70 fs/inode.c:1670
disk_part_iter_exit block/genhd.c:235 [inline]
disk_part_iter_next+0x9a/0x530 block/genhd.c:202
blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541
bdev_disk_changed+0x238/0x430 fs/block_dev.c:1246
__blkdev_get+0x86c/0xa30 fs/block_dev.c:1350
blkdev_get_by_dev fs/block_dev.c:1454 [inline]
blkdev_get_by_dev+0x26c/0x600 fs/block_dev.c:1422
blkdev_reread_part block/ioctl.c:100 [inline]
blkdev_common_ioctl+0x137e/0x17e0 block/ioctl.c:508
blkdev_ioctl+0x1ef/0x6d0 block/ioctl.c:577
block_ioctl+0xf9/0x140 fs/block_dev.c:1667
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88803268d080
which belongs to the cache bdev_cache of size 2792
The buggy address is located 40 bytes inside of
2792-byte region [ffff88803268d080, ffff88803268db68)
The buggy address belongs to the page:
page:ffffea0000c9a200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32688
head:ffffea0000c9a200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 ffffea0005110a00 0000000200000002 ffff8880109bdb40
raw: 0000000000000000 00000000800b000b 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88803268cf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
ffff88803268d000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88803268d080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88803268d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88803268d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Next message: Michael S. Tsirkin: "Re: xtensa-linux-ld: section .start VMA overlaps section .image VMA"
Previous message: Thomas Gleixner: "Re: [PATCH v4 22/22] x86/fpu/xstate: Introduce boot-parameters to control state component support"
Next in thread: syzbot: "Re: [syzbot] KASAN: use-after-free Read in disk_part_iter_next (2)"
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