================================================================== BUG: KASAN: use-after-free in relay_switch_subbuf+0x8be/0x920 kernel/relay.c:755 Read of size 8 at addr ffff8880932d2b98 by task syz-executor.0/16897 CPU: 1 PID: 16897 Comm: syz-executor.0 Not tainted 5.3.0-rc2+ #112 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:612 __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 submit_bio_wait+0x115/0x1c0 block/bio.c:987 blkdev_issue_flush+0x20d/0x300 block/blk-flush.c:449 ext4_sync_fs+0x590/0x960 fs/ext4/super.c:5142 sync_fs_one_sb fs/sync.c:80 [inline] sync_fs_one_sb+0xc7/0x100 fs/sync.c:77 iterate_supers+0x146/0x290 fs/super.c:688 ksys_sync+0xb0/0x160 fs/sync.c:115 __ia32_sys_sync+0xe/0x20 fs/sync.c:124 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 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:00007f7e13e35c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 000000000075bf28 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7e13e366d4 R13: 00000000004c6489 R14: 00000000004df408 R15: 00000000ffffffff Allocated by task 13271: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495 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 sock_alloc_file+0x50/0x180 net/socket.c:397 sock_map_fd net/socket.c:420 [inline] __sys_socket+0x150/0x220 net/socket.c:1515 __do_sys_socket net/socket.c:1520 [inline] __se_sys_socket net/socket.c:1518 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1518 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 13271: 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:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __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 ffff8880932d2b40 which belongs to the cache dentry(65:syz3) of size 288 The buggy address is located 88 bytes inside of 288-byte region [ffff8880932d2b40, ffff8880932d2c60) The buggy address belongs to the page: page:ffffea00024cb480 refcount:1 mapcount:0 mapping:ffff8880a15b21c0 index:0xffff8880932d29e0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0000665c88 ffffea000256f488 ffff8880a15b21c0 raw: ffff8880932d29e0 ffff8880932d2040 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880932d2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880932d2b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8880932d2b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880932d2c00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880932d2c80: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================