kernel/git/stable/linux.git/fs/debugfs/inode.c, branch linux-4.19.y

new helper: lookup_positive_unlocked()

2023-09-23T08:47:59+00:00

[ Upstream commit 6c2d4798a8d16cf4f3a28c3cd4af4f1dcbbb4d04 ] Most of the callers of lookup_one_len_unlocked() treat negatives are ERR_PTR(-ENOENT). Provide a helper that would do just that. Note that a pinned positive dentry remains positive - it's ->d_inode is stable, etc.; a pinned _negative_ dentry can become positive at any point as long as you are not holding its parent at least shared. So using lookup_one_len_unlocked() needs to be careful; lookup_positive_unlocked() is safer and that's what the callers end up open-coding anyway. Signed-off-by: Al Viro Stable-dep-of: 0d5a4f8f775f ("fs: Fix error checking for d_hash_and_lookup()") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

debugfs: add debugfs_lookup_and_remove()

2022-09-15T10:17:05+00:00

commit dec9b2f1e0455a151a7293c367da22ab973f713e upstream. There is a very common pattern of using debugfs_remove(debufs_lookup(..)) which results in a dentry leak of the dentry that was looked up. Instead of having to open-code the correct pattern of calling dput() on the dentry, create debugfs_lookup_and_remove() to handle this pattern automatically and properly without any memory leaks. Cc: stable Reported-by: Kuyo Chang Tested-by: Kuyo Chang Link: https://lore.kernel.org/r/YxIaQ8cSinDR881k@kroah.com Signed-off-by: Greg Kroah-Hartman

debugfs: fix use-after-free on symlink traversal

2019-05-08T05:21:48+00:00

[ Upstream commit 93b919da64c15b90953f96a536e5e61df896ca57 ] symlink body shouldn't be freed without an RCU delay. Switch debugfs to ->destroy_inode() and use of call_rcu(); free both the inode and symlink body in the callback. Similar to solution for bpf, only here it's even more obvious that ->evict_inode() can be dropped. Signed-off-by: Al Viro Signed-off-by: Sasha Levin

debugfs: fix debugfs_rename parameter checking

2019-02-15T07:10:11+00:00

commit d88c93f090f708c18195553b352b9f205e65418f upstream. debugfs_rename() needs to check that the dentries passed into it really are valid, as sometimes they are not (i.e. if the return value of another debugfs call is passed into this one.) So fix this up by properly checking if the two parent directories are errors (they are allowed to be NULL), and if the dentry to rename is not NULL or an error. Cc: stable Signed-off-by: Greg Kroah-Hartman

Revert "debugfs: inode: debugfs_create_dir uses mode permission from parent"

2018-06-13T03:52:16+00:00

This reverts commit 95cde3c59966f6371b6bcd9e4e2da2ba64ee9775. The commit had good intentions, but it breaks kvm-tool and qemu-kvm. With it in place, "lkvm run" just fails with Error: KVM_CREATE_VM ioctl Warning: Failed init: kvm__init which isn't a wonderful error message, but bisection pinpointed the problematic commit. The problem is almost certainly due to the special kvm debugfs entries created dynamically by kvm under /sys/kernel/debug/kvm/. See kvm_create_vm_debugfs() Bisected-and-reported-by: Linus Torvalds Cc: Wanpeng Li Cc: Greg Kroah-Hartman Cc: Thomas Richter Cc: Kees Cook Signed-off-by: Linus Torvalds

debugfs: inode: debugfs_create_dir uses mode permission from parent

2018-05-14T14:48:18+00:00

Currently function debugfs_create_dir() creates a new directory in the debugfs (usually mounted /sys/kernel/debug) with permission rwxr-xr-x. This is hard coded. Change this to use the parent directory permission. Output before the patch: root@s8360047 ~]# tree -dp -L 1 /sys/kernel/debug/ /sys/kernel/debug/ ├── [drwxr-xr-x] bdi ├── [drwxr-xr-x] block ├── [drwxr-xr-x] dasd ├── [drwxr-xr-x] device_component ├── [drwxr-xr-x] extfrag ├── [drwxr-xr-x] hid ├── [drwxr-xr-x] kprobes ├── [drwxr-xr-x] kvm ├── [drwxr-xr-x] memblock ├── [drwxr-xr-x] pm_qos ├── [drwxr-xr-x] qdio ├── [drwxr-xr-x] s390 ├── [drwxr-xr-x] s390dbf └── [drwx------] tracing 14 directories [root@s8360047 linux]# Output after the patch: [root@s8360047 ~]# tree -dp -L 1 /sys/kernel/debug/ sys/kernel/debug/ ├── [drwx------] bdi ├── [drwx------] block ├── [drwx------] dasd ├── [drwx------] device_component ├── [drwx------] extfrag ├── [drwx------] hid ├── [drwx------] kprobes ├── [drwx------] kvm ├── [drwx------] memblock ├── [drwx------] pm_qos ├── [drwx------] qdio ├── [drwx------] s390 ├── [drwx------] s390dbf └── [drwx------] tracing 14 directories [root@s8360047 linux]# Here is the full diff output done with: [root@s8360047 ~]# diff -u treefull.before treefull.after | sed 's-^- # -' > treefull.diff # --- treefull.before 2018-04-27 13:22:04.532824564 +0200 # +++ treefull.after 2018-04-27 13:24:12.106182062 +0200 # @@ -1,55 +1,55 @@ # /sys/kernel/debug/ # -├── [drwxr-xr-x] bdi # -│ ├── [drwxr-xr-x] 1:0 # -│ ├── [drwxr-xr-x] 1:1 # -│ ├── [drwxr-xr-x] 1:10 # -│ ├── [drwxr-xr-x] 1:11 # -│ ├── [drwxr-xr-x] 1:12 # -│ ├── [drwxr-xr-x] 1:13 # -│ ├── [drwxr-xr-x] 1:14 # -│ ├── [drwxr-xr-x] 1:15 # -│ ├── [drwxr-xr-x] 1:2 # -│ ├── [drwxr-xr-x] 1:3 # -│ ├── [drwxr-xr-x] 1:4 # -│ ├── [drwxr-xr-x] 1:5 # -│ ├── [drwxr-xr-x] 1:6 # -│ ├── [drwxr-xr-x] 1:7 # -│ ├── [drwxr-xr-x] 1:8 # -│ ├── [drwxr-xr-x] 1:9 # -│ └── [drwxr-xr-x] 94:0 # -├── [drwxr-xr-x] block # -├── [drwxr-xr-x] dasd # -│ ├── [drwxr-xr-x] 0.0.e18a # -│ ├── [drwxr-xr-x] dasda # -│ └── [drwxr-xr-x] global # -├── [drwxr-xr-x] device_component # -├── [drwxr-xr-x] extfrag # -├── [drwxr-xr-x] hid # -├── [drwxr-xr-x] kprobes # -├── [drwxr-xr-x] kvm # -├── [drwxr-xr-x] memblock # -├── [drwxr-xr-x] pm_qos # -├── [drwxr-xr-x] qdio # -│ └── [drwxr-xr-x] 0.0.f5f2 # -├── [drwxr-xr-x] s390 # -│ └── [drwxr-xr-x] stsi # -├── [drwxr-xr-x] s390dbf # -│ ├── [drwxr-xr-x] 0.0.e18a # -│ ├── [drwxr-xr-x] cio_crw # -│ ├── [drwxr-xr-x] cio_msg # -│ ├── [drwxr-xr-x] cio_trace # -│ ├── [drwxr-xr-x] dasd # -│ ├── [drwxr-xr-x] kvm-trace # -│ ├── [drwxr-xr-x] lgr # -│ ├── [drwxr-xr-x] qdio_0.0.f5f2 # -│ ├── [drwxr-xr-x] qdio_error # -│ ├── [drwxr-xr-x] qdio_setup # -│ ├── [drwxr-xr-x] qeth_card_0.0.f5f0 # -│ ├── [drwxr-xr-x] qeth_control # -│ ├── [drwxr-xr-x] qeth_msg # -│ ├── [drwxr-xr-x] qeth_setup # -│ ├── [drwxr-xr-x] vmcp # -│ └── [drwxr-xr-x] vmur # +├── [drwx------] bdi # +│ ├── [drwx------] 1:0 # +│ ├── [drwx------] 1:1 # +│ ├── [drwx------] 1:10 # +│ ├── [drwx------] 1:11 # +│ ├── [drwx------] 1:12 # +│ ├── [drwx------] 1:13 # +│ ├── [drwx------] 1:14 # +│ ├── [drwx------] 1:15 # +│ ├── [drwx------] 1:2 # +│ ├── [drwx------] 1:3 # +│ ├── [drwx------] 1:4 # +│ ├── [drwx------] 1:5 # +│ ├── [drwx------] 1:6 # +│ ├── [drwx------] 1:7 # +│ ├── [drwx------] 1:8 # +│ ├── [drwx------] 1:9 # +│ └── [drwx------] 94:0 # +├── [drwx------] block # +├── [drwx------] dasd # +│ ├── [drwx------] 0.0.e18a # +│ ├── [drwx------] dasda # +│ └── [drwx------] global # +├── [drwx------] device_component # +├── [drwx------] extfrag # +├── [drwx------] hid # +├── [drwx------] kprobes # +├── [drwx------] kvm # +├── [drwx------] memblock # +├── [drwx------] pm_qos # +├── [drwx------] qdio # +│ └── [drwx------] 0.0.f5f2 # +├── [drwx------] s390 # +│ └── [drwx------] stsi # +├── [drwx------] s390dbf # +│ ├── [drwx------] 0.0.e18a # +│ ├── [drwx------] cio_crw # +│ ├── [drwx------] cio_msg # +│ ├── [drwx------] cio_trace # +│ ├── [drwx------] dasd # +│ ├── [drwx------] kvm-trace # +│ ├── [drwx------] lgr # +│ ├── [drwx------] qdio_0.0.f5f2 # +│ ├── [drwx------] qdio_error # +│ ├── [drwx------] qdio_setup # +│ ├── [drwx------] qeth_card_0.0.f5f0 # +│ ├── [drwx------] qeth_control # +│ ├── [drwx------] qeth_msg # +│ ├── [drwx------] qeth_setup # +│ ├── [drwx------] vmcp # +│ └── [drwx------] vmur # └── [drwx------] tracing # ├── [drwxr-xr-x] events # │ ├── [drwxr-xr-x] alarmtimer Fixes: edac65eaf8d5c ("debugfs: take mode-dependent parts of debugfs_get_inode() into callers") Signed-off-by: Thomas Richter Reviewed-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

debugfs_lookup(): switch to lookup_one_len_unlocked()

2018-03-29T19:07:47+00:00

Signed-off-by: Al Viro

debugfs: Remove redundant license text

2017-11-07T19:25:03+00:00

Now that the SPDX tag is in all debugfs files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: add SPDX identifiers to all debugfs files

2017-11-07T19:25:03+00:00

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the debugfs files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Cc: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: defer debugfs_fsdata allocation to first usage

2017-11-07T19:25:03+00:00

Currently, __debugfs_create_file allocates one struct debugfs_fsdata instance for every file created. However, there are potentially many debugfs file around, most of which are never touched by userspace. Thus, defer the allocations to the first usage, i.e. to the first debugfs_file_get(). A dentry's ->d_fsdata starts out to point to the "real", user provided fops. After a debugfs_fsdata instance has been allocated (and the real fops pointer has been moved over into its ->real_fops member), ->d_fsdata is changed to point to it from then on. The two cases are distinguished by setting BIT(0) for the real fops case. struct debugfs_fsdata's foremost purpose is to track active users and to make debugfs_remove() block until they are done. Since no debugfs_fsdata instance means no active users, make debugfs_remove() return immediately in this case. Take care of possible races between debugfs_file_get() and debugfs_remove(): either debugfs_remove() must see a debugfs_fsdata instance and thus wait for possible active users or debugfs_file_get() must see a dead dentry and return immediately. Make a dentry's ->d_release(), i.e. debugfs_release_dentry(), check whether ->d_fsdata is actually a debugfs_fsdata instance before kfree()ing it. Similarly, make debugfs_real_fops() check whether ->d_fsdata is actually a debugfs_fsdata instance before returning it, otherwise emit a warning. The set of possible error codes returned from debugfs_file_get() has grown from -EIO to -EIO and -ENOMEM. Make open_proxy_open() and full_proxy_open() pass the -ENOMEM onwards to their callers. Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman