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| author | Mateusz Guzik <mjg@FreeBSD.org> | 2017-02-06 09:40:14 +0000 |
|---|---|---|
| committer | Mateusz Guzik <mjg@FreeBSD.org> | 2017-02-06 09:40:14 +0000 |
| commit | c1aaf63cb52133580093e5efe9af6dd7081f32be (patch) | |
| tree | 450e675c7635c450e7da28b551fefa58c13e3cdb /sys/kern | |
| parent | 467c82cb848afc8fc3e1540553900c9ed2c97082 (diff) | |
| download | src-c1aaf63cb52133580093e5efe9af6dd7081f32be.tar.gz src-c1aaf63cb52133580093e5efe9af6dd7081f32be.zip | |
locks: fix recursion support after recent changes
When a relevant lockstat probe is enabled the fallback primitive is called with
a constant signifying a free lock. This works fine for typical cases but breaks
with recursion, since it checks if the passed value is that of the executing
thread.
Read the value if necessary.
Notes
Notes:
svn path=/head/; revision=313335
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_mutex.c | 2 | ||||
| -rw-r--r-- | sys/kern/kern_rwlock.c | 2 | ||||
| -rw-r--r-- | sys/kern/kern_sx.c | 3 |
3 files changed, 7 insertions, 0 deletions
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index 83977bb6425e..e37fb34cd521 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -495,6 +495,8 @@ __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, uintptr_t tid, int opts, lock_delay_arg_init(&lda, NULL); #endif m = mtxlock2mtx(c); + if (__predict_false(v == MTX_UNOWNED)) + v = MTX_READ_VALUE(m); if (__predict_false(lv_mtx_owner(v) == (struct thread *)tid)) { KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index c024de5cc8cb..0a59bf94f3f8 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -812,6 +812,8 @@ __rw_wlock_hard(volatile uintptr_t *c, uintptr_t v, uintptr_t tid, lock_delay_arg_init(&lda, NULL); #endif rw = rwlock2rw(c); + if (__predict_false(v == RW_UNLOCKED)) + v = RW_READ_VALUE(rw); if (__predict_false(lv_rw_wowner(v) == (struct thread *)tid)) { KASSERT(rw->lock_object.lo_flags & LO_RECURSABLE, diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c index 4cce16d301b8..c0fc26aabd32 100644 --- a/sys/kern/kern_sx.c +++ b/sys/kern/kern_sx.c @@ -531,6 +531,9 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, uintptr_t tid, int opts, lock_delay_arg_init(&lda, NULL); #endif + if (__predict_false(x == SX_LOCK_UNLOCKED)) + x = SX_READ_VALUE(sx); + /* If we already hold an exclusive lock, then recurse. */ if (__predict_false(lv_sx_owner(x) == (struct thread *)tid)) { KASSERT((sx->lock_object.lo_flags & LO_RECURSABLE) != 0, |