From: syzbot <syzbot+29093015c21333d1c46d@syzkaller.appspotmail.com>
To: akpm@linux-foundation.org, ebiggers@google.com,
gregkh@linuxfoundation.org, jannh@google.com,
jrdr.linux@gmail.com, keescook@chromium.org,
linux-kernel@vger.kernel.org, mawilcox@microsoft.com,
rientjes@google.com, syzkaller-bugs@googlegroups.com,
viro@zeniv.linux.org.uk
Subject: Re: KASAN: use-after-free Read in relay_switch_subbuf
Date: Tue, 05 Nov 2019 23:58:07 -0800 [thread overview]
Message-ID: <000000000000c9eaf30596a8e8a5@google.com> (raw)
In-Reply-To: <0000000000002e4a260576c1589d@google.com>
syzbot has found a reproducer for the following crash on:
HEAD commit: 26bc6721 Merge tag 'for-linus-2019-11-05' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b7b7cce00000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c5e2eca3f31f9bf
dashboard link: https://syzkaller.appspot.com/bug?extid=29093015c21333d1c46d
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=132afbcce00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=179a1f8ae00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+29093015c21333d1c46d@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920
kernel/relay.c:755
Read of size 8 at addr ffff88808d5054f8 by task kworker/1:3/3760
CPU: 1 PID: 3760 Comm: kworker/1:3 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events __blk_release_queue
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:634
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755
relay_flush kernel/relay.c:883 [inline]
relay_flush+0x1c4/0x280 kernel/relay.c:867
__blk_trace_startstop.isra.0+0x216/0x630 kernel/trace/blktrace.c:662
blk_trace_shutdown+0x5f/0x90 kernel/trace/blktrace.c:746
__blk_release_queue+0x219/0x380 block/blk-sysfs.c:904
process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Allocated by task 11279:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:510 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc mm/slab.c:3319 [inline]
kmem_cache_alloc+0x121/0x710 mm/slab.c:3483
__d_alloc+0x2e/0x8c0 fs/dcache.c:1688
d_alloc+0x4d/0x280 fs/dcache.c:1767
d_alloc_parallel+0xf4/0x1c30 fs/dcache.c:2519
__lookup_slow+0x1ab/0x500 fs/namei.c:1646
lookup_one_len+0x16d/0x1a0 fs/namei.c:2533
start_creating+0xc5/0x1d0 fs/debugfs/inode.c:339
__debugfs_create_file+0x65/0x3f0 fs/debugfs/inode.c:384
debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:441
blk_create_buf_file_callback+0x33/0x40 kernel/trace/blktrace.c:444
relay_create_buf_file+0xf9/0x180 kernel/relay.c:428
relay_open_buf.part.0+0x76e/0xb60 kernel/relay.c:457
relay_open_buf kernel/relay.c:449 [inline]
relay_open kernel/relay.c:599 [inline]
relay_open+0x523/0x980 kernel/relay.c:563
do_blk_trace_setup+0x3f0/0xb50 kernel/trace/blktrace.c:526
__blk_trace_setup+0xe3/0x190 kernel/trace/blktrace.c:571
blk_trace_ioctl+0x170/0x300 kernel/trace/blktrace.c:710
blkdev_ioctl+0x126/0x1c20 block/ioctl.c:592
block_ioctl+0xee/0x130 fs/block_dev.c:1954
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 11303:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
__cache_free mm/slab.c:3425 [inline]
kmem_cache_free+0x86/0x320 mm/slab.c:3693
__d_free+0x20/0x30 fs/dcache.c:271
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292
The buggy address belongs to the object at ffff88808d5054a0
which belongs to the cache dentry of size 288
The buggy address is located 88 bytes inside of
288-byte region [ffff88808d5054a0, ffff88808d5055c0)
The buggy address belongs to the page:
page:ffffea0002354140 refcount:1 mapcount:0 mapping:ffff8880aa57b000
index:0xffff88808d505e40
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000299b6c8 ffffea0002353f08 ffff8880aa57b000
raw: ffff88808d505e40 ffff88808d505080 0000000100000009 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88808d505380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808d505400: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
> ffff88808d505480: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88808d505500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808d505580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
next prev parent reply other threads:[~2019-11-06 7:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 7:41 KASAN: use-after-free Read in relay_switch_subbuf syzbot
2019-11-06 7:58 ` syzbot [this message]
2019-11-18 6:59 ` syzbot
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