Created attachment 276187 [details] The (compressed) crafted image which causes crash - Overview Invalid pointer dereference in __del_reloc_root() when mounting a crafted btrfs image - Reproduce # mkdir mnt # mount -t btrfs 82.img mnt (Reproduced on Linux 4.17-rc5) - Comment https://elixir.bootlin.com/linux/v4.17-rc5/source/fs/btrfs/relocation.c#L1324 static void __del_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct rb_node *rb_node; struct mapping_node *node = NULL; struct reloc_control *rc = fs_info->reloc_ctl; spin_lock(&rc->reloc_root_tree.lock); rc can be NULL, which means that reloc_ctl may be not initialized - Kernel message [ 208.623313] BUG: unable to handle kernel NULL pointer dereference at 0000000000000570 [ 208.624890] PGD 80000001e9495067 P4D 80000001e9495067 PUD 1f0d81067 PMD 0 [ 208.626285] Oops: 0002 [#1] SMP KASAN PTI [ 208.627118] Modules linked in: snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm snd_timer snd mac_hid i2c_piix4 soundcore ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 multipath linear 8139too qxl drm_kms_helper crct10dif_pclmul syscopyarea crc32_pclmul sysfillrect sysimgblt fb_sys_fops ttm aesni_intel drm aes_x86_64 crypto_simd cryptd 8139cp glue_helper mii floppy pata_acpi [ 208.632054] BTRFS info (device loop0): delayed_refs has NO entry [ 208.636502] CPU: 1 PID: 1330 Comm: mount Tainted: G B W 4.17.0-rc5+ #6 [ 208.639306] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 208.641177] RIP: 0010:_raw_spin_lock+0x1e/0x40 [ 208.642200] RSP: 0018:ffff8801df437338 EFLAGS: 00010246 [ 208.643240] RAX: 0000000000000000 RBX: 0000000000000570 RCX: 0000000000000000 [ 208.644643] RDX: 0000000000000001 RSI: 0000000000000297 RDI: 0000000000000297 [ 208.646058] RBP: ffff8801df437340 R08: ffffed003ee23ebb R09: ffffed003ee23ebb [ 208.647464] R10: 0000000000000001 R11: ffffed003ee23eba R12: ffff8801f2e8c400 [ 208.648870] R13: 0000000000000000 R14: ffff8801e3a28000 R15: 0000000000000568 [ 208.650286] FS: 00007fd41a0a7840(0000) GS:ffff8801f7100000(0000) knlGS:0000000000000000 [ 208.651872] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 208.653006] CR2: 0000000000000570 CR3: 00000001e16e6000 CR4: 00000000000006e0 [ 208.654449] Call Trace: [ 208.654961] __del_reloc_root+0x5a/0x190 [ 208.655755] free_reloc_roots+0x40/0xb0 [ 208.656531] btrfs_recover_relocation+0x2fa/0x750 [ 208.657487] ? btrfs_cleanup_fs_roots+0x351/0x3b0 [ 208.658428] ? btrfs_relocate_block_group+0x370/0x370 [ 208.659433] ? qgroup_reserve+0x650/0x650 [ 208.660237] ? migrate_swap_stop+0x2e0/0x2e0 [ 208.661090] ? btrfs_check_rw_degradable+0xb0/0x240 [ 208.662077] open_ctree+0x37c4/0x3ce9 [ 208.662822] ? close_ctree+0x4a0/0x4a0 [ 208.663580] ? bdi_register_va+0x44/0x50 [ 208.664371] ? super_setup_bdi_name+0x11b/0x1a0 [ 208.665302] ? kill_block_super+0x80/0x80 [ 208.666111] ? snprintf+0x96/0xd0 [ 208.666787] btrfs_mount_root+0xae6/0xc60 [ 208.667596] ? btrfs_mount_root+0xae6/0xc60 [ 208.668449] ? pcpu_block_update_hint_alloc+0x1f5/0x2a0 [ 208.669505] ? btrfs_decode_error+0x40/0x40 [ 208.670345] ? find_next_bit+0x57/0x90 [ 208.671101] ? cpumask_next+0x1a/0x20 [ 208.671837] ? pcpu_alloc+0x449/0x8c0 [ 208.672577] ? pcpu_free_area+0x410/0x410 [ 208.673393] ? memcg_kmem_put_cache+0x1b/0xa0 [ 208.674267] ? memcpy+0x45/0x50 [ 208.674905] mount_fs+0x60/0x1a0 [ 208.675562] ? btrfs_decode_error+0x40/0x40 [ 208.676399] ? mount_fs+0x60/0x1a0 [ 208.677088] ? alloc_vfsmnt+0x309/0x360 [ 208.677880] vfs_kern_mount+0x6b/0x1a0 [ 208.678634] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 208.679671] btrfs_mount+0x209/0xb71 [ 208.680390] ? pcpu_block_update_hint_alloc+0x1f5/0x2a0 [ 208.681442] ? btrfs_remount+0x8e0/0x8e0 [ 208.682247] ? find_next_zero_bit+0x2c/0xa0 [ 208.683119] ? find_next_bit+0x57/0x90 [ 208.683876] ? cpumask_next+0x1a/0x20 [ 208.684619] ? pcpu_alloc+0x449/0x8c0 [ 208.685371] ? pcpu_free_area+0x410/0x410 [ 208.686177] ? memcg_kmem_put_cache+0x1b/0xa0 [ 208.687046] ? memcpy+0x45/0x50 [ 208.687685] mount_fs+0x60/0x1a0 [ 208.688337] ? btrfs_remount+0x8e0/0x8e0 [ 208.689121] ? mount_fs+0x60/0x1a0 [ 208.689828] ? alloc_vfsmnt+0x309/0x360 [ 208.690599] vfs_kern_mount+0x6b/0x1a0 [ 208.691352] do_mount+0x34a/0x18a0 [ 208.692039] ? lockref_put_or_lock+0xcf/0x160 [ 208.692909] ? copy_mount_string+0x20/0x20 [ 208.693742] ? memcg_kmem_put_cache+0x1b/0xa0 [ 208.694615] ? kasan_check_write+0x14/0x20 [ 208.695437] ? _copy_from_user+0x6a/0x90 [ 208.696226] ? memdup_user+0x42/0x60 [ 208.696948] ksys_mount+0x83/0xd0 [ 208.697631] __x64_sys_mount+0x67/0x80 [ 208.698385] do_syscall_64+0x78/0x170 [ 208.699122] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 208.700124] RIP: 0033:0x7fd419987b9a [ 208.700842] RSP: 002b:00007fff30668b88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 [ 208.702345] RAX: ffffffffffffffda RBX: 0000000001829030 RCX: 00007fd419987b9a [ 208.703742] RDX: 0000000001829210 RSI: 000000000182af30 RDI: 0000000001831ec0 [ 208.705134] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000014 [ 208.706533] R10: 00000000c0ed0000 R11: 0000000000000206 R12: 0000000001831ec0 [ 208.707931] R13: 0000000001829210 R14: 0000000000000000 R15: 0000000000000003 [ 208.709339] Code: 5d c3 90 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 89 e5 53 48 89 fb be 04 00 00 00 e8 c9 ac 1c ff 31 c0 ba 01 00 00 00 <f0> 0f b1 13 85 c0 75 03 5b 5d c3 89 c6 48 89 df e8 4d 20 f9 fe [ 208.713050] RIP: _raw_spin_lock+0x1e/0x40 RSP: ffff8801df437338 [ 208.714238] CR2: 0000000000000570 [ 208.714985] ---[ end trace be56bf4112c4e5e3 ]--- Found by Wen Xu and Po-Ning Tseng from SSLab, Gatech.
btrfs config: CONFIG_BTRFS_FS=y CONFIG_BTRFS_FS_POSIX_ACL=y # CONFIG_BTRFS_FS_CHECK_INTEGRITY is not set # CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set # CONFIG_BTRFS_DEBUG is not set # CONFIG_BTRFS_ASSERT is not set # CONFIG_BTRFS_FS_REF_VERIFY is not set
Fixed by https://patchwork.kernel.org/patch/10500521/ .
(In reply to Wen Xu from comment #0) > Created attachment 276187 [details] > The (compressed) crafted image which causes crash Image added to btrfs-progs fuzzed images for further testing, thanks.