On Fri, Sep 28, 2018 at 4:45 PM, syzbot <syzbot+376cea2b0ef340db3dd4@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: c127e59bee3e Merge tag 'for_v4.19-rc6' of git://git.kernel.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13b2f32a400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=dfb440e26f0a6f6f > dashboard link: https://syzkaller.appspot.com/bug?extid=376cea2b0ef340db3dd4 > 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+376cea2b0ef340db3dd4@xxxxxxxxxxxxxxxxxxxxxxxxx I guess this is overlayfs rather than printk. +overlayfs maintainers In future syzbot will avoid attributing crashes to printk, because I think it's not the first time crashes are mis-attributed to printk: https://github.com/google/syzkaller/commit/41e4b32952f4590341ae872db0abf819b4004713 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140 > RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0e714a76d4 > R13: 00000000004c32cb R14: 00000000004d4ef0 R15: 0000000000000004 > ================================================================== > BUG: KASAN: slab-out-of-bounds in string+0x298/0x2d0 lib/vsprintf.c:604 > Read of size 1 at addr ffff8801c36c66ba by task syz-executor2/27811 > > CPU: 0 PID: 27811 Comm: syz-executor2 Not tainted 4.19.0-rc5+ #36 > 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+0x1c4/0x2b4 lib/dump_stack.c:113 > print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 > string+0x298/0x2d0 lib/vsprintf.c:604 > vsnprintf+0x48e/0x1b60 lib/vsprintf.c:2293 > vscnprintf+0x2d/0x80 lib/vsprintf.c:2396 > vprintk_store+0x43/0x510 kernel/printk/printk.c:1847 > vprintk_emit+0x1c1/0x930 kernel/printk/printk.c:1905 > vprintk_default+0x28/0x30 kernel/printk/printk.c:1963 > vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 > printk+0xa7/0xcf kernel/printk/printk.c:1996 > ovl_lookup_index.cold.15+0xe8/0x1f8 fs/overlayfs/namei.c:689 > ovl_lookup+0x9f2/0x29c0 fs/overlayfs/namei.c:1022 > __lookup_hash+0x12e/0x190 fs/namei.c:1546 > do_rmdir+0x3b3/0x630 fs/namei.c:3930 > __do_sys_rmdir fs/namei.c:3959 [inline] > __se_sys_rmdir fs/namei.c:3957 [inline] > __x64_sys_rmdir+0x36/0x40 fs/namei.c:3957 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457579 > Code: 1d 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f0e714a6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 > RAX: ffffffffffffffda RBX: 00007f0e714a6c90 RCX: 0000000000457579 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140 > RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0e714a76d4 > R13: 00000000004c32cb R14: 00000000004d4ef0 R15: 0000000000000004 > > Allocated by task 27811: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > __do_kmalloc mm/slab.c:3718 [inline] > __kmalloc+0x14e/0x760 mm/slab.c:3727 > kmalloc_array include/linux/slab.h:635 [inline] > kcalloc include/linux/slab.h:646 [inline] > ovl_get_index_name_fh+0x57/0x180 fs/overlayfs/namei.c:596 > ovl_get_index_name+0x5c/0x80 fs/overlayfs/namei.c:631 > ovl_lookup_index+0xe4/0x700 fs/overlayfs/namei.c:678 > ovl_lookup+0x9f2/0x29c0 fs/overlayfs/namei.c:1022 > __lookup_hash+0x12e/0x190 fs/namei.c:1546 > do_rmdir+0x3b3/0x630 fs/namei.c:3930 > __do_sys_rmdir fs/namei.c:3959 [inline] > __se_sys_rmdir fs/namei.c:3957 [inline] > __x64_sys_rmdir+0x36/0x40 fs/namei.c:3957 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 5441: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3813 > __vunmap+0x335/0x460 mm/vmalloc.c:1532 > vfree+0x68/0x100 mm/vmalloc.c:1593 > copy_entries_to_user net/ipv4/netfilter/ip_tables.c:870 [inline] > get_entries net/ipv4/netfilter/ip_tables.c:1027 [inline] > do_ipt_get_ctl+0x9eb/0xbc0 net/ipv4/netfilter/ip_tables.c:1703 > nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] > nf_getsockopt+0x80/0xe0 net/netfilter/nf_sockopt.c:122 > ip_getsockopt+0x1af/0x240 net/ipv4/ip_sockglue.c:1577 > tcp_getsockopt+0x93/0xe0 net/ipv4/tcp.c:3583 > sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2997 > __sys_getsockopt+0x1ad/0x390 net/socket.c:1939 > __do_sys_getsockopt net/socket.c:1950 [inline] > __se_sys_getsockopt net/socket.c:1947 [inline] > __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1947 > 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 ffff8801c36c6680 > which belongs to the cache kmalloc-64 of size 64 > The buggy address is located 58 bytes inside of > 64-byte region [ffff8801c36c6680, ffff8801c36c66c0) > The buggy address belongs to the page: > page:ffffea00070db180 count:1 mapcount:0 mapping:ffff8801da800340 > index:0xffff8801c36c6380 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0006d16508 ffffea000638a588 ffff8801da800340 > raw: ffff8801c36c6380 ffff8801c36c6000 000000010000001b 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801c36c6580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801c36c6600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >> >> ffff8801c36c6680: 00 00 00 00 00 00 00 02 fc fc fc fc fc fc fc fc > > ^ > ffff8801c36c6700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801c36c6780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ================================================================== > > > --- > This bug 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 syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/0000000000003852440576ef80b2%40google.com. > For more options, visit https://groups.google.com/d/optout.
