Hello, syzbot found the following issue on:
HEAD commit: b652d2a5 Add linux-next specific files for 20200918 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=10fbecad900000 kernel config: https://syzkaller.appspot.com/x/.config?x=3cf0782933432b43 dashboard link: https://syzkaller.appspot.com/bug?extid=18d51774588492bf3f69 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+18d51774588492bf3...@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in afs_activate_cell fs/afs/cell.c:622 [inline] BUG: KASAN: use-after-free in afs_manage_cell+0xf9d/0x11c0 fs/afs/cell.c:697 Read of size 8 at addr ffff888096141a20 by task kworker/1:6/20450 CPU: 1 PID: 20450 Comm: kworker/1:6 Not tainted 5.9.0-rc5-next-20200918-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: afs afs_manage_cell Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fb lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 afs_activate_cell fs/afs/cell.c:622 [inline] afs_manage_cell+0xf9d/0x11c0 fs/afs/cell.c:697 process_one_work+0x933/0x15a0 kernel/workqueue.c:2269 process_scheduled_works kernel/workqueue.c:2331 [inline] worker_thread+0x82b/0x1120 kernel/workqueue.c:2417 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Allocated by task 5410: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmem_cache_alloc_trace+0x1a0/0x480 mm/slab.c:3548 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:666 [inline] afs_alloc_cell fs/afs/cell.c:151 [inline] afs_lookup_cell+0x5b8/0x1450 fs/afs/cell.c:262 afs_parse_source fs/afs/super.c:290 [inline] afs_parse_param+0x404/0x8c0 fs/afs/super.c:326 vfs_parse_fs_param fs/fs_context.c:117 [inline] vfs_parse_fs_param+0x203/0x550 fs/fs_context.c:98 vfs_parse_fs_string+0xe6/0x150 fs/fs_context.c:161 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:201 do_new_mount fs/namespace.c:2892 [inline] path_mount+0x1266/0x1e70 fs/namespace.c:3216 do_mount fs/namespace.c:3229 [inline] __do_sys_mount fs/namespace.c:3437 [inline] __se_sys_mount fs/namespace.c:3414 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3414 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6900: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3416 [inline] kfree+0x10e/0x2a0 mm/slab.c:3754 rcu_do_batch kernel/rcu/tree.c:2482 [inline] rcu_core+0x621/0x11d0 kernel/rcu/tree.c:2717 __do_softirq+0x203/0xab6 kernel/softirq.c:298 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2959 [inline] call_rcu+0x15e/0x7d0 kernel/rcu/tree.c:3033 afs_manage_cell+0x250/0x11c0 fs/afs/cell.c:751 process_one_work+0x933/0x15a0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 The buggy address belongs to the object at ffff888096141800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 544 bytes inside of 1024-byte region [ffff888096141800, ffff888096141c00) The buggy address belongs to the page: page:0000000010db85d7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x96141 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00024a9e48 ffffea000088a308 ffff8880aa040700 raw: 0000000000000000 ffff888096141000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888096141900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096141980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888096141a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096141a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096141b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkal...@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
