mirror_zfs/module
Fabian-Gruenbichler fa2cbd4007 zvols: prevent overflow of minor device numbers
currently, the linux kernel allows 2^20 minor devices per major device
number.  ZFS reserves blocks of 2^4 minors per zvol: 1 for the zvol
itself, the other 15 for the first partitions of that zvol. as a result,
only 2^16 such blocks are available for use.

there are no checks in place to avoid overflowing into the major device
number when more than 2^16 zvols are allocated (with volmode=dev or
default). instead of ignoring this limit, which comes with all sorts of
weird knock-on effects, detect this situation and simply fail allocating
the zvol block device early on.

without this safeguard, the kernel will reject the attempt to create an
already existing block device, but ZFS doesn't handle this error and
gets confused about which zvol occupies which minor slot, potentially
resulting in kernel NULL derefs and other issues later on.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Closes #16006
2024-04-22 09:23:23 -07:00
..
avl Suppress Clang Static Analyzer false positive in the AVL tree code. 2023-03-08 13:51:21 -08:00
icp Add BTI landing pads to the AArch64 SHA2 assembly 2023-10-04 12:36:21 -07:00
lua LUA: Backport CVE-2020-24370's patch 2024-02-08 15:22:16 -08:00
nvpair nvpair: Constify string functions 2023-03-14 15:25:50 -07:00
os zvols: prevent overflow of minor device numbers 2024-04-22 09:23:23 -07:00
unicode Illumos #15286: do_composition() needs sign awareness 2023-01-05 11:16:21 -08:00
zcommon set autotrim default to 'off' everywhere 2023-07-21 16:35:12 -07:00
zfs L2ARC: Relax locking during write 2024-04-19 10:13:38 -07:00
zstd Resolve WS-2021-0184 vulnerability in zstd 2023-02-02 15:12:51 -08:00
.gitignore FreeBSD: Ignore symlink to i386 includes 2022-08-02 16:34:23 -07:00
Kbuild.in linux 6.7 compat: rework shrinker setup for heap allocations 2023-12-21 11:03:08 -08:00
Makefile.bsd Finally drop long disabled vdev cache. 2023-06-09 12:40:55 -07:00
Makefile.in check-zstd-symbols: also ignore __pfx_ symbols 2023-09-19 08:52:06 -07:00