================================================================== BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 Read of size 8 at addr ffff88808aa63358 by task syz-executor.5/15465 CPU: 1 PID: 15465 Comm: syz-executor.5 Not tainted 5.3.0-rc6+ #147 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_rq+0x185/0x1f0 kernel/trace/blktrace.c:813 blk_add_trace_rq_insert+0x180/0x1e0 kernel/trace/blktrace.c:820 trace_block_rq_insert include/trace/events/block.h:192 [inline] blk_mq_sched_request_inserted+0x1a5/0x330 block/blk-mq-sched.c:356 dd_insert_request block/mq-deadline.c:509 [inline] dd_insert_requests+0x2c4/0x980 block/mq-deadline.c:545 blk_mq_sched_insert_request+0x58c/0x720 block/blk-mq-sched.c:401 blk_execute_rq_nowait+0x139/0x180 block/blk-exec.c:62 sg_common_write.isra.0+0xfa7/0x22c0 drivers/scsi/sg.c:838 sg_write.part.0+0x855/0xf10 drivers/scsi/sg.c:709 sg_write+0x6e/0x93 drivers/scsi/sg.c:617 do_loop_readv_writev fs/read_write.c:717 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_write fs/read_write.c:972 [inline] do_iter_write+0x4a0/0x610 fs/read_write.c:951 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015 do_writev+0x15b/0x330 fs/read_write.c:1058 __do_sys_writev fs/read_write.c:1131 [inline] __se_sys_writev fs/read_write.c:1128 [inline] __x64_sys_writev+0x75/0xb0 fs/read_write.c:1128 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:00007fee73d68c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879 RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fee73d696d4 R13: 00000000004c6bc5 R14: 00000000004e13e0 R15: 00000000ffffffff Allocated by task 14776: 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_pseudo+0x1e/0x70 fs/dcache.c:1817 alloc_file_pseudo+0xe2/0x280 fs/file_table.c:225 anon_inode_getfile fs/anon_inodes.c:91 [inline] anon_inode_getfile+0xda/0x200 fs/anon_inodes.c:74 __do_sys_perf_event_open+0x10cc/0x2890 kernel/events/core.c:11009 __se_sys_perf_event_open kernel/events/core.c:10783 [inline] __x64_sys_perf_event_open+0xbe/0x150 kernel/events/core.c:10783 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 14774: 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 fs/dcache.c:271 [inline] dentry_free+0xe9/0x160 fs/dcache.c:348 __dentry_kill+0x457/0x600 fs/dcache.c:593 dentry_kill fs/dcache.c:686 [inline] dput+0x819/0xde0 fs/dcache.c:859 __fput+0x424/0x890 fs/file_table.c:293 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88808aa63300 which belongs to the cache dentry(49:syz2) of size 288 The buggy address is located 88 bytes inside of 288-byte region [ffff88808aa63300, ffff88808aa63420) The buggy address belongs to the page: page:ffffea00022a98c0 refcount:1 mapcount:0 mapping:ffff88808b8de1c0 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002544608 ffffea000254bf08 ffff88808b8de1c0 raw: 0000000000000000 ffff88808aa63040 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808aa63200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808aa63280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88808aa63300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808aa63380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808aa63400: fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 00 ==================================================================