==================================================================
BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755
Read of size 8 at addr ffff8880414f2cf8 by task syz-executor.2/31861
CPU: 0 PID: 31861 Comm: syz-executor.2 Not tainted 5.3.0-rc6 #146
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
__kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
kasan_report+0x12/0x17 mm/kasan/common.c:618
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755
relay_reserve include/linux/relay.h:261 [inline]
trace_note.isra.0+0x5b8/0x6e0 kernel/trace/blktrace.c:93
trace_note_tsk kernel/trace/blktrace.c:124 [inline]
__blk_add_trace+0xb70/0xe10 kernel/trace/blktrace.c:264
blk_add_trace_bio.isra.0+0x19c/0x220 kernel/trace/blktrace.c:865
blk_add_trace_bio_queue+0x46/0x60 kernel/trace/blktrace.c:902
trace_block_bio_queue include/trace/events/block.h:357 [inline]
generic_make_request_checks+0x16c3/0x21a0 block/blk-core.c:954
generic_make_request+0x8f/0xb50 block/blk-core.c:1006
submit_bio+0x104/0x4d0 block/blk-core.c:1163
blk_next_bio+0x4a/0x60 block/blk-lib.c:19
__blkdev_issue_zero_pages+0x151/0x430 block/blk-lib.c:284
blkdev_issue_zeroout+0x434/0x4c0 block/blk-lib.c:378
blk_ioctl_zeroout block/ioctl.c:264 [inline]
blkdev_ioctl+0x13d4/0x1c1a block/ioctl.c:531
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+0xfd/0x6a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459879
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8cfa4fec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879
RDX: 0000000020000080 RSI: 000000000000127f RDI: 0000000000000008
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8cfa4ff6d4
R13: 00000000004c0f8b R14: 00000000004d41b0 R15: 00000000ffffffff
Allocated by task 18724:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:493 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:501
slab_post_alloc_hook mm/slab.h:520 [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_anon fs/dcache.c:1786 [inline]
d_alloc_cursor+0x3f/0xe0 fs/dcache.c:1792
dcache_dir_open+0x37/0x90 fs/libfs.c:78
do_dentry_open+0x4df/0x1250 fs/open.c:797
vfs_open+0xa0/0xd0 fs/open.c:906
do_last fs/namei.c:3416 [inline]
path_openat+0x10e9/0x4630 fs/namei.c:3533
do_filp_open+0x1a1/0x280 fs/namei.c:3563
do_sys_open+0x3fe/0x5d0 fs/open.c:1089
__do_sys_open fs/open.c:1107 [inline]
__se_sys_open fs/open.c:1102 [inline]
__x64_sys_open+0x7e/0xc0 fs/open.c:1102
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 22113:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:455
kasan_slab_free+0xe/0x10 mm/kasan/common.c:463
__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:2114 [inline]
rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323
__do_softirq+0x262/0x98c kernel/softirq.c:292
The buggy address belongs to the object at ffff8880414f2ca0
which belongs to the cache dentry(49:syz2) of size 288
The buggy address is located 88 bytes inside of
288-byte region [ffff8880414f2ca0, ffff8880414f2dc0)
The buggy address belongs to the page:
page:ffffea0001053c80 refcount:1 mapcount:0 mapping:ffff88808dcba700 index:0xffff8880414f2300
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0001051188 ffffea00024ada88 ffff88808dcba700
raw: ffff8880414f2300 ffff8880414f2040 0000000100000008 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880414f2b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880414f2c00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff8880414f2c80: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880414f2d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880414f2d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================