mirror_zfs/include/spl/sys
jdike 4c98586daf Fix lockdep recursive locking false positive in dbuf_destroy
lockdep reports a possible recursive lock in dbuf_destroy.

It is true that dbuf_destroy is acquiring the dn_dbufs_mtx
on one dnode while holding it on another dnode.  However,
it is impossible for these to be the same dnode because,
among other things,dbuf_destroy checks MUTEX_HELD before
acquiring the mutex.

This fix defines a class NESTED_SINGLE == 1 and changes
that lock to call mutex_enter_nested with a subclass of
NESTED_SINGLE.

In order to make the userspace code compile,
include/sys/zfs_context.h now defines mutex_enter_nested and
NESTED_SINGLE.

This is the lockdep report:

[  122.950921] ============================================
[  122.950921] WARNING: possible recursive locking detected
[  122.950921] 4.19.29-4.19.0-debug-d69edad5368c1166 #1 Tainted: G           O
[  122.950921] --------------------------------------------
[  122.950921] dbu_evict/1457 is trying to acquire lock:
[  122.950921] 0000000083e9cbcf (&dn->dn_dbufs_mtx){+.+.}, at: dbuf_destroy+0x3c0/0xdb0 [zfs]
[  122.950921]
               but task is already holding lock:
[  122.950921] 0000000055523987 (&dn->dn_dbufs_mtx){+.+.}, at: dnode_evict_dbufs+0x90/0x740 [zfs]
[  122.950921]
               other info that might help us debug this:
[  122.950921]  Possible unsafe locking scenario:

[  122.950921]        CPU0
[  122.950921]        ----
[  122.950921]   lock(&dn->dn_dbufs_mtx);
[  122.950921]   lock(&dn->dn_dbufs_mtx);
[  122.950921]
                *** DEADLOCK ***

[  122.950921]  May be due to missing lock nesting notation

[  122.950921] 1 lock held by dbu_evict/1457:
[  122.950921]  #0: 0000000055523987 (&dn->dn_dbufs_mtx){+.+.}, at: dnode_evict_dbufs+0x90/0x740 [zfs]
[  122.950921]
               stack backtrace:
[  122.950921] CPU: 0 PID: 1457 Comm: dbu_evict Tainted: G           O      4.19.29-4.19.0-debug-d69edad5368c1166 #1
[  122.950921] Hardware name: Supermicro H8SSL-I2/H8SSL-I2, BIOS 080011  03/13/2009
[  122.950921] Call Trace:
[  122.950921]  dump_stack+0x91/0xeb
[  122.950921]  __lock_acquire+0x2ca7/0x4f10
[  122.950921]  lock_acquire+0x153/0x330
[  122.950921]  dbuf_destroy+0x3c0/0xdb0 [zfs]
[  122.950921]  dbuf_evict_one+0x1cc/0x3d0 [zfs]
[  122.950921]  dbuf_rele_and_unlock+0xb84/0xd60 [zfs]
[  122.950921]  dnode_evict_dbufs+0x3a6/0x740 [zfs]
[  122.950921]  dmu_objset_evict+0x7a/0x500 [zfs]
[  122.950921]  dsl_dataset_evict_async+0x70/0x480 [zfs]
[  122.950921]  taskq_thread+0x979/0x1480 [spl]
[  122.950921]  kthread+0x2e7/0x3e0
[  122.950921]  ret_from_fork+0x27/0x50

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jeff Dike <jdike@akamai.com>
Closes #8984
2019-09-25 11:27:49 -07:00
..
acl.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
atomic.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
byteorder.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
callb.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
callo.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
cmn_err.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
condvar.h Linux 4.18 compat: inode timespec -> timespec64 2018-06-19 21:51:18 -07:00
console.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
cred.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
ctype.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
debug.h VERIFY3P() message is missing a space character 2019-06-07 12:39:13 -07:00
disp.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
dkio.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
errno.h Update build system and packaging 2018-05-29 16:00:33 -07:00
fcntl.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
file.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
inttypes.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
isa_defs.h Fix kernel unaligned access on sparc64 2018-07-11 13:10:40 -07:00
kmem_cache.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
kmem.h OpenZFS 9284 - arc_reclaim_thread has 2 jobs 2018-12-26 13:22:28 -08:00
kobj.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
kstat.h Restrict kstats and print real pointers 2019-04-04 18:57:06 -07:00
list.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
Makefile.am Add TRIM support 2019-03-29 09:13:20 -07:00
mode.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
mutex.h Fix lockdep recursive locking false positive in dbuf_destroy 2019-09-25 11:27:49 -07:00
param.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
proc.h Unbreak build on Linux kernel < 3.10 2019-04-08 14:59:24 -07:00
processor.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
procfs_list.h Restrict kstats and print real pointers 2019-04-04 18:57:06 -07:00
random.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
rwlock.h Linux 5.2 compat: rw_tryupgrade() 2019-05-23 13:46:33 -07:00
shrinker.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
sid.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
signal.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
stat.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
strings.h Linux 2.6.39 compat: Test if kstrtoul() exists 2019-06-07 12:39:13 -07:00
sunddi.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
sysmacros.h Create /proc/sys/kernel/spl/gitrev with git hash 2018-10-08 21:57:02 -07:00
systeminfo.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
taskq.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
thread.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
time.h Linux 4.18 compat: Use ktime_get_coarse_real_ts64() 2019-01-28 10:11:03 -08:00
timer.h kernel timer API rework 2019-09-25 11:27:46 -07:00
tsd.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
types32.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
types.h Linux 5.1 compat: Drop ULLONG_MAX and LLONG_MAX definitions 2019-05-07 09:55:40 -07:00
uio.h deadlock between mm_sem and tx assign in zfs_write() and page fault 2018-10-16 11:11:24 -07:00
user.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
vfs.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
vmem.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
vmsystm.h Linux 5.0 compat: Use totalhigh_pages() 2019-05-04 16:40:48 -07:00
vnode.h Remove vn_set_fs_pwd()/vn_set_pwd() (no need to be at / during insmod) 2019-09-25 11:27:46 -07:00
wait.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
zmod.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
zone.h Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00