06f79675b7
VOP_RMDIR() is called with both parent and child directory vnodes locked. The relookup operation performed by the unionfs implementation may relock both vnodes. Accordingly, unionfs_relookup() drops the parent vnode lock, but the child vnode lock is never dropped. Although relookup() will very likely try to relock the child vnode which is already locked, in most cases this doesn't produce a deadlock because unionfs_lock() forces LK_CANRECURSE (!). However, relocking of the parent vnode while the child vnode remains locked effectively reverses the expected parent->child lock order, which can produce a deadlock e.g. in the presence of a concurrent unionfs_lookup() operation. Address the issue by dropping the child lock around the unionfs_relookup() call in unionfs_rmdir(). Reported by: pho Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D32986
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| Directory | Description |
|---|---|
| bin | System/user commands. |
| cddl | Various commands and libraries under the Common Development and Distribution License. |
| contrib | Packages contributed by 3rd parties. |
| crypto | Cryptography stuff (see crypto/README). |
| etc | Template files for /etc. |
| gnu | Various commands and libraries under the GNU Public License. Please see gnu/COPYING and gnu/COPYING.LIB for more information. |
| include | System include files. |
| kerberos5 | Kerberos5 (Heimdal) package. |
| lib | System libraries. |
| libexec | System daemons. |
| release | Release building Makefile & associated tools. |
| rescue | Build system for statically linked /rescue utilities. |
| sbin | System commands. |
| secure | Cryptographic libraries and commands. |
| share | Shared resources. |
| stand | Boot loader sources. |
| sys | Kernel sources. |
sys/arch/conf |
Kernel configuration files. GENERIC is the configuration used in release builds. NOTES contains documentation of all possible entries. |
| tests | Regression tests which can be run by Kyua. See tests/README for additional information. |
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| usr.sbin | System administration commands. |
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