mirror_zfs/module/os/freebsd/zfs
rob-wing 28251d81d7
FreeBSD: don't verify recycled vnode for zfs control directory
Under certain loads, the following panic is hit:

    panic: page fault
    KDB: stack backtrace:
    #0 0xffffffff805db025 at kdb_backtrace+0x65
    #1 0xffffffff8058e86f at vpanic+0x17f
    #2 0xffffffff8058e6e3 at panic+0x43
    #3 0xffffffff808adc15 at trap_fatal+0x385
    #4 0xffffffff808adc6f at trap_pfault+0x4f
    #5 0xffffffff80886da8 at calltrap+0x8
    #6 0xffffffff80669186 at vgonel+0x186
    #7 0xffffffff80669841 at vgone+0x31
    #8 0xffffffff8065806d at vfs_hash_insert+0x26d
    #9 0xffffffff81a39069 at sfs_vgetx+0x149
    #10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #11 0xffffffff8065a28c at lookup+0x45c
    #12 0xffffffff806594b9 at namei+0x259
    #13 0xffffffff80676a33 at kern_statat+0xf3
    #14 0xffffffff8067712f at sys_fstatat+0x2f
    #15 0xffffffff808ae50c at amd64_syscall+0x10c
    #16 0xffffffff808876bb at fast_syscall_common+0xf8

The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.

After adding the necessary vop, the bug progresses to the following
panic:

    panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
    cpuid = 17
    KDB: stack backtrace:
    #0 0xffffffff805e29c5 at kdb_backtrace+0x65
    #1 0xffffffff8059620f at vpanic+0x17f
    #2 0xffffffff81a27f4a at spl_panic+0x3a
    #3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    #4 0xffffffff8066fdee at vinactivef+0xde
    #5 0xffffffff80670b8a at vgonel+0x1ea
    #6 0xffffffff806711e1 at vgone+0x31
    #7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    #8 0xffffffff81a39069 at sfs_vgetx+0x149
    #9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #10 0xffffffff80661c2c at lookup+0x45c
    #11 0xffffffff80660e59 at namei+0x259
    #12 0xffffffff8067e3d3 at kern_statat+0xf3
    #13 0xffffffff8067eacf at sys_fstatat+0x2f
    #14 0xffffffff808b5ecc at amd64_syscall+0x10c
    #15 0xffffffff8088f07b at fast_syscall_common+0xf8

This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.

Fix this by dropping the assertion.

FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <avg@FreeBSD.org>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Rob Wing <rob.wing@klarasystems.com>
Co-authored-by: Rob Wing <rob.wing@klarasystems.com>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes #14501
2023-02-21 17:26:33 -08:00
..
abd_os.c FreeBSD: use zero_region instead of allocating a dedicated page 2022-05-04 11:46:37 -07:00
arc_os.c Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
crypto_os.c FreeBSD: Improve crypto_dispatch() handling 2022-06-17 15:38:51 -07:00
dmu_os.c Remove bcopy(), bzero(), bcmp() 2022-03-15 15:13:42 -07:00
event_os.c FreeBSD: add knlist_init_sx() for exclusive locks 2022-09-06 09:48:57 -07:00
hkdf.c Remove bcopy(), bzero(), bcmp() 2022-03-15 15:13:42 -07:00
kmod_core.c Reduce need for contiguous memory for ioctls 2023-02-13 16:35:59 -08:00
spa_os.c FreeBSD: Fix potential boot panic with bad label 2022-12-22 11:50:09 -08:00
sysctl_os.c Turn default_bs and default_ibs into ZFS_MODULE_PARAMs 2023-01-11 09:38:20 -08:00
vdev_file.c Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
vdev_geom.c Improve too large physical ashift handling 2022-09-08 10:30:53 -07:00
vdev_label_os.c Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_acl.c Cleanup of dead code suggested by Clang Static Analyzer (#14380) 2023-01-17 09:57:12 -08:00
zfs_ctldir.c FreeBSD: don't verify recycled vnode for zfs control directory 2023-02-21 17:26:33 -08:00
zfs_debug.c Cleanup: Replace oldstyle struct hack with C99 flexible array members 2023-01-12 16:00:03 -08:00
zfs_dir.c Fix unprotected zfs_znode_dmu_fini 2023-01-19 16:59:05 -08:00
zfs_file_os.c FreeBSD: handle V_PCATCH 2022-09-20 15:22:32 -07:00
zfs_ioctl_compat.c freebsd: add ifdefs around legacy ioctl support 2022-11-07 15:55:26 -08:00
zfs_ioctl_os.c libzfs: On FreeBSD, use MNT_NOWAIT with getfsstat 2021-06-08 07:36:43 -06:00
zfs_racct.c module: zfs: fix unused, remove argsused 2021-12-23 09:42:47 -08:00
zfs_vfsops.c Fix per-jail zfs.mount_snapshot setting 2023-02-21 17:23:01 -08:00
zfs_vnops_os.c FreeBSD: stop using buffer cache-only routines on sync 2022-11-29 09:35:25 -08:00
zfs_znode.c Fix unprotected zfs_znode_dmu_fini 2023-01-19 16:59:05 -08:00
zio_crypt.c Cleanup: Use kmem_zalloc() instead of memset() to zero memory 2023-01-12 15:59:28 -08:00
zvol_os.c Optionally skip zil_close during zvol_create_minor_impl 2022-11-08 12:38:08 -08:00