It seems like this is the xlog_alloc_log error path. We didn't really change anything in the circular ioclogs queue handling, so maybe thish has been there before, but xfs_buf wasn't wired up to kasan to catch it? Either way I suspect the right thing to do is to replace the list with an array based lookup. I'll look into that, maybe a reproducer appears until then. On Wed, Jun 26, 2019 at 11:50:06PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 1dd45f17 Add linux-next specific files for 20190626 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=172479e9a00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c1222640552e42a5 > dashboard link: https://syzkaller.appspot.com/bug?extid=b75afdbe271a0d7ac4f6 > compiler: gcc (GCC) 9.0.0 20181231 (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+b75afdbe271a0d7ac4f6@xxxxxxxxxxxxxxxxxxxxxxxxx > > XFS (loop5): Mounting V4 Filesystem > ================================================================== > BUG: KASAN: use-after-free in xlog_alloc_log+0x1266/0x1380 > fs/xfs/xfs_log.c:1478 > Read of size 8 at addr ffff8880693e2990 by task syz-executor.5/12241 > > CPU: 1 PID: 12241 Comm: syz-executor.5 Not tainted 5.2.0-rc6-next-20190626 > #23 > 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:614 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 > xlog_alloc_log+0x1266/0x1380 fs/xfs/xfs_log.c:1478 > xfs_log_mount+0xdc/0x780 fs/xfs/xfs_log.c:580 > xfs_mountfs+0xdb9/0x1be0 fs/xfs/xfs_mount.c:815 > xfs_fs_fill_super+0xca6/0x16c0 fs/xfs/xfs_super.c:1740 > mount_bdev+0x304/0x3c0 fs/super.c:1346 > xfs_fs_mount+0x35/0x40 fs/xfs/xfs_super.c:1814 > legacy_get_tree+0x108/0x220 fs/fs_context.c:661 > vfs_get_tree+0x8e/0x390 fs/super.c:1476 > do_new_mount fs/namespace.c:2791 [inline] > do_mount+0x138c/0x1c00 fs/namespace.c:3111 > ksys_mount+0xdb/0x150 fs/namespace.c:3320 > __do_sys_mount fs/namespace.c:3334 [inline] > __se_sys_mount fs/namespace.c:3331 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3331 > do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45bf6a > Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 9d 8d fb ff c3 66 2e 0f > 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff > 0f 83 7a 8d fb ff c3 66 0f 1f 84 00 00 00 00 00 > RSP: 002b:00007fac99605a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007fac99605b40 RCX: 000000000045bf6a > RDX: 00007fac99605ae0 RSI: 0000000020000000 RDI: 00007fac99605b00 > RBP: 0000000000000001 R08: 00007fac99605b40 R09: 00007fac99605ae0 > R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000004 > R13: 00000000004c858e R14: 00000000004df0e0 R15: 00000000ffffffff > > Allocated by task 12241: > save_stack+0x23/0x90 mm/kasan/common.c:71 > set_track mm/kasan/common.c:79 [inline] > __kasan_kmalloc mm/kasan/common.c:489 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 > __do_kmalloc mm/slab.c:3656 [inline] > __kmalloc+0x163/0x770 mm/slab.c:3665 > kmalloc include/linux/slab.h:556 [inline] > kmem_alloc+0xd2/0x200 fs/xfs/kmem.c:24 > kmem_zalloc fs/xfs/kmem.h:73 [inline] > xlog_alloc_log+0xbf4/0x1380 fs/xfs/xfs_log.c:1420 > xfs_log_mount+0xdc/0x780 fs/xfs/xfs_log.c:580 > xfs_mountfs+0xdb9/0x1be0 fs/xfs/xfs_mount.c:815 > xfs_fs_fill_super+0xca6/0x16c0 fs/xfs/xfs_super.c:1740 > mount_bdev+0x304/0x3c0 fs/super.c:1346 > xfs_fs_mount+0x35/0x40 fs/xfs/xfs_super.c:1814 > legacy_get_tree+0x108/0x220 fs/fs_context.c:661 > vfs_get_tree+0x8e/0x390 fs/super.c:1476 > do_new_mount fs/namespace.c:2791 [inline] > do_mount+0x138c/0x1c00 fs/namespace.c:3111 > ksys_mount+0xdb/0x150 fs/namespace.c:3320 > __do_sys_mount fs/namespace.c:3334 [inline] > __se_sys_mount fs/namespace.c:3331 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3331 > do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 12241: > save_stack+0x23/0x90 mm/kasan/common.c:71 > set_track mm/kasan/common.c:79 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 > __cache_free mm/slab.c:3426 [inline] > kfree+0x10a/0x2c0 mm/slab.c:3757 > kvfree+0x61/0x70 mm/util.c:488 > kmem_free fs/xfs/kmem.h:66 [inline] > xlog_alloc_log+0xea9/0x1380 fs/xfs/xfs_log.c:1480 > xfs_log_mount+0xdc/0x780 fs/xfs/xfs_log.c:580 > xfs_mountfs+0xdb9/0x1be0 fs/xfs/xfs_mount.c:815 > xfs_fs_fill_super+0xca6/0x16c0 fs/xfs/xfs_super.c:1740 > mount_bdev+0x304/0x3c0 fs/super.c:1346 > xfs_fs_mount+0x35/0x40 fs/xfs/xfs_super.c:1814 > legacy_get_tree+0x108/0x220 fs/fs_context.c:661 > vfs_get_tree+0x8e/0x390 fs/super.c:1476 > do_new_mount fs/namespace.c:2791 [inline] > do_mount+0x138c/0x1c00 fs/namespace.c:3111 > ksys_mount+0xdb/0x150 fs/namespace.c:3320 > __do_sys_mount fs/namespace.c:3334 [inline] > __se_sys_mount fs/namespace.c:3331 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3331 > do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8880693e2900 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 144 bytes inside of > 1024-byte region [ffff8880693e2900, ffff8880693e2d00) > The buggy address belongs to the page: > page:ffffea0001a4f880 refcount:1 mapcount:0 mapping:ffff8880aa400c40 > index:0x0 compound_mapcount: 0 > flags: 0x1fffc0000010200(slab|head) > raw: 01fffc0000010200 ffffea00018ec788 ffffea0002473908 ffff8880aa400c40 > raw: 0000000000000000 ffff8880693e2000 0000000100000007 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8880693e2880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8880693e2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8880693e2980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8880693e2a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8880693e2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > 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#status for how to communicate with syzbot. ---end quoted text---
