Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull /proc/sys dcache lookup fix from Al Viro:
"Fix for the breakage spotted by Neil in the interplay between
/proc/sys ->d_compare() weirdness and parallel lookups"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix proc_sys_compare() handling of in-lookup dentries
+12
-8
+1
-1
fs/proc/inode.c
+1
-1
fs/proc/inode.c
+11
-7
fs/proc/proc_sysctl.c
+11
-7
fs/proc/proc_sysctl.c
···
918
918
struct ctl_table_header *head;
919
919
struct inode *inode;
920
920
921
-
/* Although proc doesn't have negative dentries, rcu-walk means
922
-
* that inode here can be NULL */
923
-
/* AV: can it, indeed? */
924
-
inode = d_inode_rcu(dentry);
925
-
if (!inode)
926
-
return 1;
927
921
if (name->len != len)
928
922
return 1;
929
923
if (memcmp(name->name, str, len))
930
924
return 1;
931
-
head = rcu_dereference(PROC_I(inode)->sysctl);
925
+
926
+
// false positive is fine here - we'll recheck anyway
927
+
if (d_in_lookup(dentry))
928
+
return 0;
929
+
930
+
inode = d_inode_rcu(dentry);
931
+
// we just might have run into dentry in the middle of __dentry_kill()
932
+
if (!inode)
933
+
return 1;
934
+
935
+
head = READ_ONCE(PROC_I(inode)->sysctl);
932
936
return !head || !sysctl_is_seen(head);
933
937
}
934
938