On Thu, Aug 23, 2018 at 4:35 PM syzbot <syzbot+8ab6f1042021b4eed062@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: cc3d190b12b3 Add linux-next specific files for 20180822 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=107d322e400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ce7f661707bc9904 > dashboard link: https://syzkaller.appspot.com/bug?extid=8ab6f1042021b4eed062 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+8ab6f1042021b4eed062@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: use-after-free in ceph_destroy_options+0xe0/0x110 > net/ceph/ceph_common.c:289 > Read of size 8 at addr ffff8801d8f4dd50 by task syz-executor2/7977 > > CPU: 0 PID: 7977 Comm: syz-executor2 Not tainted 4.18.0-next-20180822+ #45 > 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+0x1c9/0x2b4 lib/dump_stack.c:113 > print_address_description+0x6c/0x20b mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > ceph_destroy_options+0xe0/0x110 net/ceph/ceph_common.c:289 > ceph_mount+0xeab/0x1cc0 fs/ceph/super.c:1047 > legacy_get_tree+0x131/0x460 fs/fs_context.c:732 > vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746 > do_new_mount fs/namespace.c:2627 [inline] > do_mount+0x6f9/0x1e30 fs/namespace.c:2951 > ksys_mount+0x12d/0x140 fs/namespace.c:3167 > __do_sys_mount fs/namespace.c:3181 [inline] > __se_sys_mount fs/namespace.c:3178 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457089 > Code: fd b4 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fae7dd45c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007fae7dd466d4 RCX: 0000000000457089 > RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000020000000 > RBP: 00000000009300a0 R08: 00000000200000c0 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004d2750 R14: 00000000004c7bdf R15: 0000000000000000 > > Allocated by task 7977: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x730 mm/slab.c:3620 > kmalloc include/linux/slab.h:513 [inline] > kzalloc include/linux/slab.h:707 [inline] > ceph_parse_options+0xfe/0x1230 net/ceph/ceph_common.c:355 > parse_mount_options fs/ceph/super.c:491 [inline] > ceph_mount+0x4b9/0x1cc0 fs/ceph/super.c:1036 > legacy_get_tree+0x131/0x460 fs/fs_context.c:732 > vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746 > do_new_mount fs/namespace.c:2627 [inline] > do_mount+0x6f9/0x1e30 fs/namespace.c:2951 > ksys_mount+0x12d/0x140 fs/namespace.c:3167 > __do_sys_mount fs/namespace.c:3181 [inline] > __se_sys_mount fs/namespace.c:3178 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 7977: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xd9/0x210 mm/slab.c:3813 > ceph_destroy_options+0xd4/0x110 net/ceph/ceph_common.c:295 > ceph_destroy_client+0x139/0x1a0 net/ceph/ceph_common.c:680 > create_fs_client fs/ceph/super.c:677 [inline] > ceph_mount+0xf6e/0x1cc0 fs/ceph/super.c:1043 > legacy_get_tree+0x131/0x460 fs/fs_context.c:732 > vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746 > do_new_mount fs/namespace.c:2627 [inline] > do_mount+0x6f9/0x1e30 fs/namespace.c:2951 > ksys_mount+0x12d/0x140 fs/namespace.c:3167 > __do_sys_mount fs/namespace.c:3181 [inline] > __se_sys_mount fs/namespace.c:3178 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801d8f4dc80 > which belongs to the cache kmalloc-256 of size 256 > The buggy address is located 208 bytes inside of > 256-byte region [ffff8801d8f4dc80, ffff8801d8f4dd80) > The buggy address belongs to the page: > page:ffffea000763d340 count:1 mapcount:0 mapping:ffff8801dac007c0 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0006c0e448 ffffea00072ca688 ffff8801dac007c0 > raw: 0000000000000000 ffff8801d8f4d000 000000010000000c 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801d8f4dc00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801d8f4dc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8801d8f4dd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8801d8f4dd80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb > ffff8801d8f4de00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== Thanks for the report, I'll prepare a patch. Ilya
