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77831e1738
freebsd-nq/module/zfs
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Kohsuke Kawaguchi 77831e1738 Reduce the stack usage of dsl_dataset_remove_clones_key 
dataset_remove_clones_key does recursion, so if the recursion goes
deep it can overrun the linux kernel stack size of 8KB. I have seen
this happen in the actual deployment, and subsequently confirmed it by
running a test workload on a custom-built kernel that uses 32KB stack.

See the following stack trace as an example of the case where it would
have run over the 8KB stack kernel:

        Depth    Size   Location    (42 entries)
        -----    ----   --------
  0)    11192      72   __kmalloc+0x2e/0x240
  1)    11120     144   kmem_alloc_debug+0x20e/0x500
  2)    10976      72   dbuf_hold_impl+0x4a/0xa0
  3)    10904     120   dbuf_prefetch+0xd3/0x280
  4)    10784      80   dmu_zfetch_dofetch.isra.5+0x10f/0x180
  5)    10704     240   dmu_zfetch+0x5f7/0x10e0
  6)    10464     168   dbuf_read+0x71e/0x8f0
  7)    10296     104   dnode_hold_impl+0x1ee/0x620
  8)    10192      16   dnode_hold+0x19/0x20
  9)    10176      88   dmu_buf_hold+0x42/0x1b0
 10)    10088     144   zap_lockdir+0x48/0x730
 11)     9944     128   zap_cursor_retrieve+0x1c4/0x2f0
 12)     9816     392   dsl_dataset_remove_clones_key.isra.14+0xab/0x190
 13)     9424     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 14)     9032     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 15)     8640     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 16)     8248     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 17)     7856     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 18)     7464     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 19)     7072     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 20)     6680     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 21)     6288     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 22)     5896     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 23)     5504     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 24)     5112     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 25)     4720     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 26)     4328     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 27)     3936     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 28)     3544     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 29)     3152     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 30)     2760     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 31)     2368     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 32)     1976     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 33)     1584     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 34)     1192     232   dsl_dataset_destroy_sync+0x311/0xf60
 35)      960      72   dsl_sync_task_group_sync+0x12f/0x230
 36)      888     168   dsl_pool_sync+0x48b/0x5c0
 37)      720     184   spa_sync+0x417/0xb00
 38)      536     184   txg_sync_thread+0x325/0x5b0
 39)      352      48   thread_generic_wrapper+0x7a/0x90
 40)      304     128   kthread+0xc0/0xd0
 41)      176     176   ret_from_fork+0x7c/0xb0

This change reduces the stack usage in dsl_dataset_remove_clones_key
by allocating structures in heap, not in stack.  This is not a fundamental
fix, as one can create an arbitrary large data set that runs over any
fixed size stack, but this will make the problem far less likely.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kohsuke Kawaguchi <kk@kohsuke.org>
Closes #1726
2013-09-25 15:18:32 -07:00
..
arc.c Illumos #3464 2013-09-04 16:01:24 -07:00
bplist.c Illumos #3464 2013-09-04 16:01:24 -07:00
bpobj.c Illumos #3464 2013-09-04 16:01:24 -07:00
bptree.c Illumos #3498 panic in arc_read() 2013-07-02 13:34:31 -07:00
dbuf.c Illumos #3464 2013-09-04 16:01:24 -07:00
ddt_zap.c Add ddt_object_count() error handling 2012-10-29 08:57:45 -07:00
ddt.c Fix incorrect assertions in ddt_phys_decref and ddt_sync_entry 2013-05-06 14:10:55 -07:00
dmu_diff.c Illumos #3464 2013-09-04 16:01:24 -07:00
dmu_object.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
dmu_objset.c Fix dmu_objset_find_dp() KM_SLEEP warning 2013-09-11 11:49:32 -07:00
dmu_send.c Illumos #3464 2013-09-04 16:01:24 -07:00
dmu_traverse.c Illumos #3464 2013-09-04 16:01:24 -07:00
dmu_tx.c Illumos #3464 2013-09-04 16:01:24 -07:00
dmu_zfetch.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dmu.c Illumos #3464 2013-09-04 16:01:24 -07:00
dnode_sync.c Illumos #3464 2013-09-04 16:01:24 -07:00
dnode.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_dataset.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_deadlist.c Illumos #3104: eliminate empty bpobjs 2013-01-08 10:35:43 -08:00
dsl_deleg.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_destroy.c Reduce the stack usage of dsl_dataset_remove_clones_key 2013-09-25 15:18:32 -07:00
dsl_dir.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_pool.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_prop.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_scan.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_synctask.c Illumos #3464 2013-09-04 16:01:24 -07:00
dsl_userhold.c Illumos #3464 2013-09-04 16:01:24 -07:00
fm.c Condition variable usage, zevent_cv 2012-10-15 16:01:54 -07:00
gzip.c Fix zmod.h usage in userspace 2010-08-31 08:38:46 -07:00
lz4.c Linux 3.9 compat: Undefine GCC_VERSION 2013-03-06 15:48:48 -08:00
lzjb.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
Makefile.in Illumos #3464 2013-09-04 16:01:24 -07:00
metaslab.c Illumos #3464 2013-09-04 16:01:24 -07:00
refcount.c Illumos #3464 2013-09-04 16:01:24 -07:00
rrwlock.c Illumos #3464 2013-09-04 16:01:24 -07:00
sa.c Illumos #3464 2013-09-04 16:01:24 -07:00
sha256.c Add linux sha2 support 2010-08-31 13:41:59 -07:00
spa_boot.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
spa_config.c Illumos #3639 zpool.cache should skip over readonly pools 2013-08-07 16:13:56 -07:00
spa_errlog.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
spa_history.c Illumos #3464 2013-09-04 16:01:24 -07:00
spa_misc.c Illumos #3464 2013-09-04 16:01:24 -07:00
spa.c Illumos #3464 2013-09-04 16:01:24 -07:00
space_map.c Illumos #3464 2013-09-04 16:01:24 -07:00
txg.c Illumos #3464 2013-09-04 16:01:24 -07:00
uberblock.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
unique.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
vdev_cache.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
vdev_disk.c Use GFP_NOIO in vdev_disk_io_flush() 2013-07-10 14:12:21 -07:00
vdev_file.c Illumos #3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock contention 2013-05-06 14:05:37 -07:00
vdev_label.c Illumos #3090 and #3102 2013-01-08 10:35:42 -08:00
vdev_mirror.c Improve N-way mirror performance 2013-07-11 13:53:50 -07:00
vdev_missing.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev_queue.c Illumos #3618 ::zio dcmd does not show timestamp data 2013-08-12 16:46:50 -07:00
vdev_raidz.c Illumos #3006 2013-06-19 15:14:10 -07:00
vdev_root.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev.c Illumos #3618 ::zio dcmd does not show timestamp data 2013-08-12 16:46:50 -07:00
zap_leaf.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-05 08:44:58 -07:00
zap_micro.c Illumos #3006 2013-06-19 15:14:10 -07:00
zap.c Illumos #3006 2013-06-19 15:14:10 -07:00
zfeature_common.c Illumos #3035 LZ4 compression support in ZFS and GRUB 2013-01-29 09:28:20 -08:00
zfeature.c Illumos #3104: eliminate empty bpobjs 2013-01-08 10:35:43 -08:00
zfs_acl.c Avoid gcc -Werror=maybe-uninitialized warnings 2013-01-28 09:10:29 -08:00
zfs_byteswap.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
zfs_ctldir.c Illumos #3464 2013-09-04 16:01:24 -07:00
zfs_debug.c Illumos #3006 2013-06-19 15:14:10 -07:00
zfs_dir.c Trivial spelling fix 2013-04-19 15:43:16 -07:00
zfs_fm.c 3246 ZFS I/O deadman thread 2013-05-01 17:05:52 -07:00
zfs_fuid.c Drop HAVE_XVATTR macros 2011-03-02 11:44:34 -08:00
zfs_ioctl.c Illumos #3464 2013-09-04 16:01:24 -07:00
zfs_log.c Revert "Remove TSD zfs_fsyncer_key" 2012-12-20 09:56:28 -08:00
zfs_onexit.c Add linux kernel device support 2010-08-31 13:41:50 -07:00
zfs_replay.c Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
zfs_rlock.c Illumos #3006 2013-06-19 15:14:10 -07:00
zfs_sa.c Revert "Use SA_HDL_PRIVATE for SA xattrs" 2012-08-25 09:25:56 -07:00
zfs_vfsops.c Illumos #3464 2013-09-04 16:01:24 -07:00
zfs_vnops.c Linux 3.11 compat: fops->iterate() 2013-08-15 16:19:07 -07:00
zfs_znode.c Fix uninitialized variables 2013-09-13 13:31:24 -07:00
zil.c Illumos #3464 2013-09-04 16:01:24 -07:00
zio_checksum.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zio_compress.c Illumos #3035 LZ4 compression support in ZFS and GRUB 2013-01-29 09:28:20 -08:00
zio_inject.c 3246 ZFS I/O deadman thread 2013-05-01 17:05:52 -07:00
zio.c Illumos #3464 2013-09-04 16:01:24 -07:00
zle.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zpl_ctldir.c Linux 3.11 compat: fops->iterate() 2013-08-15 16:19:07 -07:00
zpl_export.c Implement .commit_metadata hook for NFS export 2012-10-03 10:49:45 -07:00
zpl_file.c Linux 3.11 compat: fops->iterate() 2013-08-15 16:19:07 -07:00
zpl_inode.c Fix zpl_mknod() return values 2013-09-13 13:31:24 -07:00
zpl_super.c Fix arc_adapt() spinning in iterate_supers_type() 2013-07-17 09:28:06 -07:00
zpl_xattr.c Use directory xattrs for symlinks 2013-08-22 13:30:44 -07:00
zrlock.c Export ZFS symbols needed by Lustre. 2010-09-17 16:24:15 -07:00
zvol.c Illumos #3464 2013-09-04 16:01:24 -07:00