mirror_zfs/lib
Matthew Ahrens 018f26041d
deadlock between spa_errlog_lock and dp_config_rwlock
There is a lock order inversion deadlock between `spa_errlog_lock` and
`dp_config_rwlock`:

A thread in `spa_delete_dataset_errlog()` is running from a sync task.
It is holding the `dp_config_rwlock` for writer (see
`dsl_sync_task_sync()`), and waiting for the `spa_errlog_lock`.

A thread in `dsl_pool_config_enter()` is holding the `spa_errlog_lock`
(see `spa_get_errlog_size()`) and waiting for the `dp_config_rwlock` (as
reader).

Note that this was introduced by #12812.

This commit address this by defining the lock ordering to be
dp_config_rwlock first, then spa_errlog_lock / spa_errlist_lock.
spa_get_errlog() and spa_get_errlog_size() can acquire the locks in this
order, and then process_error_block() and get_head_and_birth_txg() can
verify that the dp_config_rwlock is already held.

Additionally, a buffer overrun in `spa_get_errlog()` is corrected.  Many
code paths didn't check if `*count` got to zero, instead continuing to
overwrite past the beginning of the userspace buffer at `uaddr`.

Tested by having some errors in the pool (via `zinject -t data
/path/to/file`), one thread running `zpool iostat 0.001`, and another
thread runs `zfs destroy` (in a loop, although it hits the first time).
This reproduces the problem easily without the fix, and works with the
fix.

Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #14239
Closes #14289
2022-12-22 11:48:49 -08:00
..
libavl cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libefi Fix multiplication converted to larger type 2022-10-28 09:30:37 -07:00
libicp Introduce BLAKE3 checksums as an OpenZFS feature 2022-06-08 15:55:57 -07:00
libnvpair Fix GCC 12 compilation errors 2022-11-30 13:45:53 -08:00
libshare Ubuntu 22.04 integration: Cppcheck 2022-11-18 11:26:50 -08:00
libspl freebsd: simplify MD isa_defs.h 2022-11-07 15:55:37 -08:00
libtpool Add <limits.h> header 2022-11-28 13:24:17 -08:00
libunicode cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libuutil libuutil: deobfuscate internal pointers 2022-11-03 09:57:05 -07:00
libzfs deadlock between spa_errlog_lock and dp_config_rwlock 2022-12-22 11:48:49 -08:00
libzfs_core Don't leak packed recieved proprties 2022-11-29 09:51:35 -08:00
libzfsbootenv Fix unchecked return values and unused return values 2022-09-23 16:52:03 -07:00
libzpool Add <limits.h> header 2022-11-28 13:24:17 -08:00
libzstd cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libzutil Aligned free for aligned alloc 2022-10-26 15:08:31 -07:00
Makefile.am autoconf: use include directives instead of recursing down lib 2022-05-10 10:18:11 -07:00