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btrfs: fix iput() on error pointer after error during orphan cleanup
commitcbaee87f2e
upstream. At btrfs_orphan_cleanup(), if we can't find an inode (btrfs_iget() returns an -ENOENT error pointer), we proceed with 'ret' set to -ENOENT and the inode pointer set to ERR_PTR(-ENOENT). Later when we proceed to the body of the following if statement: if (ret == -ENOENT || inode->i_nlink) { (...) trans = btrfs_start_transaction(root, 1); if (IS_ERR(trans)) { ret = PTR_ERR(trans); iput(inode); goto out; } (...) ret = btrfs_del_orphan_item(trans, root, found_key.objectid); btrfs_end_transaction(trans); if (ret) { iput(inode); goto out; } continue; } If we get an error from btrfs_start_transaction() or from the call to btrfs_del_orphan_item() we end calling iput() against an inode pointer that has a value of ERR_PTR(-ENOENT), resulting in a crash with the following trace: [876.667] BUG: kernel NULL pointer dereference, address: 0000000000000096 [876.667] #PF: supervisor read access in kernel mode [876.667] #PF: error_code(0x0000) - not-present page [876.667] PGD 0 P4D 0 [876.668] Oops: 0000 [#1] PREEMPT SMP PTI [876.668] CPU: 0 PID: 2356187 Comm: mount Tainted: G W 6.4.0-rc6-btrfs-next-134+ #1 [876.668] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [876.668] RIP: 0010:iput+0xa/0x20 [876.668] Code: ff ff ff 66 (...) [876.669] RSP: 0018:ffffafa9c0c9f9d0 EFLAGS: 00010282 [876.669] RAX: ffffffffffffffe4 RBX: 000000000009453b RCX: 0000000000000000 [876.669] RDX: 0000000000000001 RSI: ffffafa9c0c9f930 RDI: fffffffffffffffe [876.669] RBP: ffff95c612f3b800 R08: 0000000000000001 R09: ffffffffffffffe4 [876.670] R10: 00018f2a71010000 R11: 000000000ead96e3 R12: ffff95cb7d6909a0 [876.670] R13: fffffffffffffffe R14: ffff95c60f477000 R15: 00000000ffffffe4 [876.670] FS: 00007f5fbe30a840(0000) GS:ffff95ccdfa00000(0000) knlGS:0000000000000000 [876.670] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [876.671] CR2: 0000000000000096 CR3: 000000055e9f6004 CR4: 0000000000370ef0 [876.671] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [876.671] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [876.672] Call Trace: [876.744] <TASK> [876.744] ? __die_body+0x1b/0x60 [876.744] ? page_fault_oops+0x15d/0x450 [876.745] ? __kmem_cache_alloc_node+0x47/0x410 [876.745] ? do_user_addr_fault+0x65/0x8a0 [876.745] ? exc_page_fault+0x74/0x170 [876.746] ? asm_exc_page_fault+0x22/0x30 [876.746] ? iput+0xa/0x20 [876.746] btrfs_orphan_cleanup+0x221/0x330 [btrfs] [876.746] btrfs_lookup_dentry+0x58f/0x5f0 [btrfs] [876.747] btrfs_lookup+0xe/0x30 [btrfs] [876.747] __lookup_slow+0x82/0x130 [876.785] walk_component+0xe5/0x160 [876.786] path_lookupat.isra.0+0x6e/0x150 [876.786] filename_lookup+0xcf/0x1a0 [876.786] ? mod_objcg_state+0xd2/0x360 [876.786] ? obj_cgroup_charge+0xf5/0x110 [876.787] ? should_failslab+0xa/0x20 [876.787] ? kmem_cache_alloc+0x47/0x450 [876.787] vfs_path_lookup+0x51/0x90 [876.788] mount_subtree+0x8d/0x130 [876.788] btrfs_mount+0x149/0x410 [btrfs] [876.788] ? __kmem_cache_alloc_node+0x47/0x410 [876.788] ? vfs_parse_fs_param+0xc0/0x110 [876.789] legacy_get_tree+0x24/0x50 [876.834] vfs_get_tree+0x22/0xd0 [876.852] path_mount+0x2d8/0x9c0 [876.852] do_mount+0x79/0x90 [876.852] __x64_sys_mount+0x8e/0xd0 [876.853] do_syscall_64+0x38/0x90 [876.899] entry_SYSCALL_64_after_hwframe+0x72/0xdc [876.958] RIP: 0033:0x7f5fbe50b76a [876.959] Code: 48 8b 0d a9 (...) [876.959] RSP: 002b:00007fff01925798 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [876.959] RAX: ffffffffffffffda RBX: 00007f5fbe694264 RCX: 00007f5fbe50b76a [876.960] RDX: 0000561bde6c8720 RSI: 0000561bde6bdec0 RDI: 0000561bde6c31a0 [876.960] RBP: 0000561bde6bdc70 R08: 0000000000000000 R09: 0000000000000001 [876.960] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [876.960] R13: 0000561bde6c31a0 R14: 0000561bde6c8720 R15: 0000561bde6bdc70 [876.960] </TASK> So fix this by setting 'inode' to NULL whenever we get an error from btrfs_iget(), and to make the code simpler, stop testing for 'ret' being -ENOENT to check if we have an inode - instead test for 'inode' being NULL or not. Having a NULL 'inode' prevents any iput() call from crashing, as iput() ignores NULL inode pointers. Also, stop testing for a NULL return value from btrfs_iget() with PTR_ERR_OR_ZERO(), because btrfs_iget() never returns NULL - in case an inode is not found, it returns ERR_PTR(-ENOENT), and in case of memory allocation failure, it returns ERR_PTR(-ENOMEM). We also don't need the extra iput() calls on the error branches for the btrfs_start_transaction() and btrfs_del_orphan_item() calls, as we have already called iput() before, so remove them. Fixes:a13bb2c038
("btrfs: add missing iputs on orphan cleanup failure") CC: stable@vger.kernel.org # 6.4 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
c3e395fe7c
commit
a21a43e433
1 changed files with 10 additions and 10 deletions
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@ -3546,11 +3546,14 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
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found_key.type = BTRFS_INODE_ITEM_KEY;
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found_key.offset = 0;
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inode = btrfs_iget(fs_info->sb, last_objectid, root);
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ret = PTR_ERR_OR_ZERO(inode);
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if (ret && ret != -ENOENT)
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goto out;
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if (IS_ERR(inode)) {
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ret = PTR_ERR(inode);
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inode = NULL;
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if (ret != -ENOENT)
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goto out;
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}
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if (ret == -ENOENT && root == fs_info->tree_root) {
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if (!inode && root == fs_info->tree_root) {
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struct btrfs_root *dead_root;
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int is_dead_root = 0;
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@ -3611,8 +3614,8 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
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* deleted but wasn't. The inode number may have been reused,
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* but either way, we can delete the orphan item.
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*/
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if (ret == -ENOENT || inode->i_nlink) {
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if (!ret) {
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if (!inode || inode->i_nlink) {
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if (inode) {
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ret = btrfs_drop_verity_items(BTRFS_I(inode));
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iput(inode);
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if (ret)
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@ -3621,7 +3624,6 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
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trans = btrfs_start_transaction(root, 1);
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if (IS_ERR(trans)) {
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ret = PTR_ERR(trans);
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iput(inode);
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goto out;
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}
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btrfs_debug(fs_info, "auto deleting %Lu",
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@ -3629,10 +3631,8 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
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ret = btrfs_del_orphan_item(trans, root,
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found_key.objectid);
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btrfs_end_transaction(trans);
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if (ret) {
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iput(inode);
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if (ret)
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goto out;
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}
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continue;
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}
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