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Fix the default path to zpool.cache for FreeBSD #1

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Signed-off-by: Allan Jude allanjude@freebsd.org

@allanjude allanjude force-pushed the zof_zpoolcache_bootfix branch 7 times, most recently from 017f81e to 4dd45a0 Compare March 27, 2020 19:41
- Fix the default path to zpool.cache for FreeBSD

- Restore ability to read files (zpool.cache) before root is mounted

- spa_config_load() calls zfs_file_read() with resid=NULL
  Add a condition to not dereference resid if it is null

Signed-off-by: Allan Jude <allanjude@freebsd.org>
@allanjude allanjude force-pushed the zof_zpoolcache_bootfix branch from 4dd45a0 to b186986 Compare March 27, 2020 22:25
allanjude pushed a commit that referenced this pull request Jul 30, 2021
`zpool_do_import()` passes `argv[0]`, (optionally) `argv[1]`, and
`pool_specified` to `import_pools()`.  If `pool_specified==FALSE`, the
`argv[]` arguments are not used.  However, these values may be off the
end of the `argv[]` array, so loading them could dereference unmapped
memory.  This error is reported by the asan build:

```
=================================================================
==6003==ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 8 at 0x6030000004a8 thread T0
    #0 0x562a078b50eb in zpool_do_import zpool_main.c:3796
    #1 0x562a078858c5 in main zpool_main.c:10709
    openzfs#2 0x7f5115231bf6 in __libc_start_main
    openzfs#3 0x562a07885eb9 in _start

0x6030000004a8 is located 0 bytes to the right of 24-byte region
allocated by thread T0 here:
    #0 0x7f5116ac6b40 in __interceptor_malloc
    #1 0x562a07885770 in main zpool_main.c:10699
    openzfs#2 0x7f5115231bf6 in __libc_start_main
```

This commit passes NULL for these arguments if they are off the end
of the `argv[]` array.

Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes openzfs#12339
allanjude pushed a commit that referenced this pull request Jan 26, 2023
Before this patch, in zfs_domount, if zfs_root or d_make_root fails, we
leave zfsvfs != NULL. This will lead to execution of the error handling
`if` statement at the `out` label, and hence to a call to
dmu_objset_disown and zfsvfs_free.

However, zfs_umount, which we call upon failure of zfs_root and
d_make_root already does dmu_objset_disown and zfsvfs_free.

I suppose this patch rather adds to the brittleness of this part of the
code base, but I don't want to invest more time in this right now.
To add a regression test, we'd need some kind of fault injection
facility for zfs_root or d_make_root, which doesn't exist right now.
And even then, I think that regression test would be too closely tied
to the implementation.

To repro the double-disown / double-free, do the following:
1. patch zfs_root to always return an error
2. mount a ZFS filesystem

Here's the stack trace you would see then:

  VERIFY3(ds->ds_owner == tag) failed (0000000000000000 == ffff9142361e8000)
  PANIC at dsl_dataset.c:1003:dsl_dataset_disown()
  Showing stack for process 28332
  CPU: 2 PID: 28332 Comm: zpool Tainted: G           O      5.10.103-1.nutanix.el7.x86_64 #1
  Call Trace:
   dump_stack+0x74/0x92
   spl_dumpstack+0x29/0x2b [spl]
   spl_panic+0xd4/0xfc [spl]
   dsl_dataset_disown+0xe9/0x150 [zfs]
   dmu_objset_disown+0xd6/0x150 [zfs]
   zfs_domount+0x17b/0x4b0 [zfs]
   zpl_mount+0x174/0x220 [zfs]
   legacy_get_tree+0x2b/0x50
   vfs_get_tree+0x2a/0xc0
   path_mount+0x2fa/0xa70
   do_mount+0x7c/0xa0
   __x64_sys_mount+0x8b/0xe0
   do_syscall_64+0x38/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Co-authored-by: Christian Schwarz <christian.schwarz@nutanix.com>
Signed-off-by: Christian Schwarz <christian.schwarz@nutanix.com>
Closes openzfs#14025
0mp pushed a commit that referenced this pull request Mar 31, 2023
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
    openzfs#2 0xffffffff8058e6e3 at panic+0x43
    openzfs#3 0xffffffff808adc15 at trap_fatal+0x385
    openzfs#4 0xffffffff808adc6f at trap_pfault+0x4f
    openzfs#5 0xffffffff80886da8 at calltrap+0x8
    openzfs#6 0xffffffff80669186 at vgonel+0x186
    openzfs#7 0xffffffff80669841 at vgone+0x31
    openzfs#8 0xffffffff8065806d at vfs_hash_insert+0x26d
    openzfs#9 0xffffffff81a39069 at sfs_vgetx+0x149
    openzfs#10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    openzfs#11 0xffffffff8065a28c at lookup+0x45c
    openzfs#12 0xffffffff806594b9 at namei+0x259
    openzfs#13 0xffffffff80676a33 at kern_statat+0xf3
    openzfs#14 0xffffffff8067712f at sys_fstatat+0x2f
    openzfs#15 0xffffffff808ae50c at amd64_syscall+0x10c
    openzfs#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
    openzfs#2 0xffffffff81a27f4a at spl_panic+0x3a
    openzfs#3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    openzfs#4 0xffffffff8066fdee at vinactivef+0xde
    openzfs#5 0xffffffff80670b8a at vgonel+0x1ea
    openzfs#6 0xffffffff806711e1 at vgone+0x31
    openzfs#7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    openzfs#8 0xffffffff81a39069 at sfs_vgetx+0x149
    openzfs#9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    openzfs#10 0xffffffff80661c2c at lookup+0x45c
    openzfs#11 0xffffffff80660e59 at namei+0x259
    openzfs#12 0xffffffff8067e3d3 at kern_statat+0xf3
    openzfs#13 0xffffffff8067eacf at sys_fstatat+0x2f
    openzfs#14 0xffffffff808b5ecc at amd64_syscall+0x10c
    openzfs#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 openzfs#14501
allanjude pushed a commit that referenced this pull request Apr 7, 2023
`zpool_do_import()` passes `argv[0]`, (optionally) `argv[1]`, and
`pool_specified` to `import_pools()`.  If `pool_specified==FALSE`, the
`argv[]` arguments are not used.  However, these values may be off the
end of the `argv[]` array, so loading them could dereference unmapped
memory.  This error is reported by the asan build:

```
=================================================================
==6003==ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 8 at 0x6030000004a8 thread T0
    #0 0x562a078b50eb in zpool_do_import zpool_main.c:3796
    #1 0x562a078858c5 in main zpool_main.c:10709
    openzfs#2 0x7f5115231bf6 in __libc_start_main
    openzfs#3 0x562a07885eb9 in _start

0x6030000004a8 is located 0 bytes to the right of 24-byte region
allocated by thread T0 here:
    #0 0x7f5116ac6b40 in __interceptor_malloc
    #1 0x562a07885770 in main zpool_main.c:10699
    openzfs#2 0x7f5115231bf6 in __libc_start_main
```

This commit passes NULL for these arguments if they are off the end
of the `argv[]` array.

Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes openzfs#12339
allanjude pushed a commit that referenced this pull request Apr 7, 2023
Before this patch, in zfs_domount, if zfs_root or d_make_root fails, we
leave zfsvfs != NULL. This will lead to execution of the error handling
`if` statement at the `out` label, and hence to a call to
dmu_objset_disown and zfsvfs_free.

However, zfs_umount, which we call upon failure of zfs_root and
d_make_root already does dmu_objset_disown and zfsvfs_free.

I suppose this patch rather adds to the brittleness of this part of the
code base, but I don't want to invest more time in this right now.
To add a regression test, we'd need some kind of fault injection
facility for zfs_root or d_make_root, which doesn't exist right now.
And even then, I think that regression test would be too closely tied
to the implementation.

To repro the double-disown / double-free, do the following:
1. patch zfs_root to always return an error
2. mount a ZFS filesystem

Here's the stack trace you would see then:

  VERIFY3(ds->ds_owner == tag) failed (0000000000000000 == ffff9142361e8000)
  PANIC at dsl_dataset.c:1003:dsl_dataset_disown()
  Showing stack for process 28332
  CPU: 2 PID: 28332 Comm: zpool Tainted: G           O      5.10.103-1.nutanix.el7.x86_64 #1
  Call Trace:
   dump_stack+0x74/0x92
   spl_dumpstack+0x29/0x2b [spl]
   spl_panic+0xd4/0xfc [spl]
   dsl_dataset_disown+0xe9/0x150 [zfs]
   dmu_objset_disown+0xd6/0x150 [zfs]
   zfs_domount+0x17b/0x4b0 [zfs]
   zpl_mount+0x174/0x220 [zfs]
   legacy_get_tree+0x2b/0x50
   vfs_get_tree+0x2a/0xc0
   path_mount+0x2fa/0xa70
   do_mount+0x7c/0xa0
   __x64_sys_mount+0x8b/0xe0
   do_syscall_64+0x38/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Co-authored-by: Christian Schwarz <christian.schwarz@nutanix.com>
Signed-off-by: Christian Schwarz <christian.schwarz@nutanix.com>
Closes openzfs#14025
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