while mounting the poc image user-provided, kernel panics due to the NULL deference of @tree->inode. ======================================================================== [ 109.663024] BTRFS error: found node 12582912 29360127 on insert of 37748736 29360127 [ 109.663032] BUG: kernel NULL pointer dereference, address: 0000000000000028 [ 109.664494] #PF: supervisor read access in kernel mode [ 109.665543] #PF: error_code(0x0000) - not-present page [ 109.666598] PGD 0 P4D 0 [ 109.667119] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 109.668015] CPU: 14 PID: 641 Comm: mount Tainted: G W O 5.11.0-rc1-custom #45 [ 109.669707] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.14.0-1 04/01/2014 [ 109.671607] RIP: 0010:extent_io_tree_panic.isra.0+0x6/0x30 [btrfs] [ 109.672911] Code: 89 fe 48 c7 c7 20 0e aa c0 48 89 e5 e8 3a b9 ee dd 0f 0b be c0 13 00 00 48 c7 c7 48 0e aa c0 e8 d1 ff ff ff 0f 1f 44 00 00 55 <48> 8b 47 28 89 f1 49 c7 c0 70 0e aa c0 ba a9 02 00 00 48 c7 c6 00 [ 109.676740] RSP: 0018:ffffb76c814fb948 EFLAGS: 00010282 [ 109.677808] RAX: 00000000ffffffef RBX: 0000000001bfffff RCX: 0000000000000000 [ 109.679271] RDX: ffffb76c814fb99c RSI: 00000000ffffffef RDI: 0000000000000000 [ 109.680722] RBP: ffffb76c814fb9e0 R08: 0000000000000001 R09: 0000000000000001 [ 109.682179] R10: ffffb76c814fb658 R11: 0000000000000000 R12: ffff9acac353e500 [ 109.683629] R13: ffff9acac89a8228 R14: ffff9acac353e8c0 R15: 0000000002400000 [ 109.685092] FS: 00007fb1f7dc3580(0000) GS:ffff9acb48c00000(0000) knlGS:0000000000000000 [ 109.686749] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 109.687927] CR2: 0000000000000028 CR3: 0000000103982000 CR4: 0000000000750ee0 [ 109.689380] PKRU: 55555554 [ 109.689935] Call Trace: [ 109.690438] ? set_extent_bit.cold+0x30/0x98 [btrfs] [ 109.718452] set_extent_bits_nowait+0x1d/0x20 [btrfs] [ 109.741357] add_extent_mapping+0x1e0/0x2f0 [btrs] [ 109.761474] read_one_chunk+0x33c/0x420 [btrfs] [ 109.781087] btrfs_read_chunk_tree+0x6a4/0x870 [btrfs] [ 109.800486] ? kvm_sched_clock_read+0x18/0x40 [ 109.819669] open_ctree+0xb32/0x1734 [btrfs] [ 109.838794] ? bdi_register_va+0x1b/0x20 [ 109.857812] ? super_setup_bdi_name+0x79/0xd0 [ 109.876880] btrfs_mount_root.cold+0x12/0xeb [btrfs] [ 109.895860] ? __kmalloc_track_caller+0x217/0x3b0 [ 109.914731] legacy_get_tree+0x34/0x60 [ 109.933041] vfs_get_tree+0x2d/0xc0 [ 109.950757] vfs_kern_mount.part.0+0x78/0xc0 [ 109.968262] vfs_kern_mount+0x13/0x20 [ 109.984976] btrfs_mount+0x11f/0x3c0 [btrfs] [ 110.001475] ? kfree+0x5ff/0x670 [ 110.017410] ? __kmalloc_track_caller+0x217/0x3b0 [ 110.033439] legacy_get_tree+0x34/0x60 [ 110.049000] vfs_get_tree+0x2d/0xc0 [ 110.064604] path_mount+0x48c/0xd30 [ 110.080199] __x64_sys_mount+0x108/0x140 [ 110.095918] do_syscall_64+0x38/0x50 [ 110.111366] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 110.126869] RIP: 0033:0x7fb1f7f42f6e [ 110.141818] Code: 48 8b 0d 05 0f 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d2 0e 0c 00 f7 d8 64 89 01 48 [ 110.188250] RSP: 002b:00007fff152c68a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [ 110.220331] RAX: ffffffffffffffda RBX: 00007fb1f8067264 RCX: 00007fb1f7f42f6e [ 110.237474] RDX: 00005608be216360 RSI: 00005608be208690 RDI: 00005608be20f6c0 [ 110.254718] RBP: 00005608be208440 R08: 0000000000000000 R09: 0000000000000001 [ 110.272042] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 110.288955] R13: 00005608be20f6c0 R14: 00005608be216360 R15: 00005608be208440 [ 110.305969] Modules linked in: [ 110.458051] CR2: 0000000000000028 [ 110.478548] ---[ end trace 3499c8e7baa57952 ]--- ========================================================================
The image has a device extent whose end(29360127) is less than the start (37748736). btrfs did warn but continued to insert the invalid sate to device::alloc_state tree. Then tree_insert() returned -EEXIST because of the duplicate end. extent_io_tree_panic() was to be called. However, the @tree->inode is NULL in extent_io_tree_panic() and it should be NULL here because that device::alloc_state io tree's member @private is NULL by design. Just pass @tree->fs_info as parameter to extent_io_tree_panic() directly. Let it panic as expected at least. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=208929 Fixes: 05912a3c04eb ("btrfs: drop extent_io_ops::tree_fs_info callback") Signed-off-by: Su Yue <l...@damenly.su> --- I don't know why insert_state() code only warns about the invalid state and extent io operations are used in so many places. So just send the simple patch. --- fs/btrfs/extent_io.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 6e3b72e63e42..c9cee458e001 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -676,9 +676,7 @@ alloc_extent_state_atomic(struct extent_state *prealloc) static void extent_io_tree_panic(struct extent_io_tree *tree, int err) { - struct inode *inode = tree->private_data; - - btrfs_panic(btrfs_sb(inode->i_sb), err, + btrfs_panic(tree->fs_info, err, "locking error: extent tree was modified by another thread while locked"); } -- 2.29.2
