CVE-2021-47145

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> btrfs: do not BUG_ON in link_to_fixup_dir<br /> <br /> While doing error injection testing I got the following panic<br /> <br /> kernel BUG at fs/btrfs/tree-log.c:1862!<br /> invalid opcode: 0000 [#1] SMP NOPTI<br /> CPU: 1 PID: 7836 Comm: mount Not tainted 5.13.0-rc1+ #305<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014<br /> RIP: 0010:link_to_fixup_dir+0xd5/0xe0<br /> RSP: 0018:ffffb5800180fa30 EFLAGS: 00010216<br /> RAX: fffffffffffffffb RBX: 00000000fffffffb RCX: ffff8f595287faf0<br /> RDX: ffffb5800180fa37 RSI: ffff8f5954978800 RDI: 0000000000000000<br /> RBP: ffff8f5953af9450 R08: 0000000000000019 R09: 0000000000000001<br /> R10: 000151f408682970 R11: 0000000120021001 R12: ffff8f5954978800<br /> R13: ffff8f595287faf0 R14: ffff8f5953c77dd0 R15: 0000000000000065<br /> FS: 00007fc5284c8c40(0000) GS:ffff8f59bbd00000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 00007fc5287f47c0 CR3: 000000011275e002 CR4: 0000000000370ee0<br /> Call Trace:<br /> replay_one_buffer+0x409/0x470<br /> ? btree_read_extent_buffer_pages+0xd0/0x110<br /> walk_up_log_tree+0x157/0x1e0<br /> walk_log_tree+0xa6/0x1d0<br /> btrfs_recover_log_trees+0x1da/0x360<br /> ? replay_one_extent+0x7b0/0x7b0<br /> open_ctree+0x1486/0x1720<br /> btrfs_mount_root.cold+0x12/0xea<br /> ? __kmalloc_track_caller+0x12f/0x240<br /> legacy_get_tree+0x24/0x40<br /> vfs_get_tree+0x22/0xb0<br /> vfs_kern_mount.part.0+0x71/0xb0<br /> btrfs_mount+0x10d/0x380<br /> ? vfs_parse_fs_string+0x4d/0x90<br /> legacy_get_tree+0x24/0x40<br /> vfs_get_tree+0x22/0xb0<br /> path_mount+0x433/0xa10<br /> __x64_sys_mount+0xe3/0x120<br /> do_syscall_64+0x3d/0x80<br /> entry_SYSCALL_64_after_hwframe+0x44/0xae<br /> <br /> We can get -EIO or any number of legitimate errors from<br /> btrfs_search_slot(), panicing here is not the appropriate response. The<br /> error path for this code handles errors properly, simply return the<br /> error.