diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/elision-unlock.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/elision-unlock.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c b/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c index 43c5a67df2..14e0680ee9 100644 --- a/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c +++ b/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c @@ -1,5 +1,5 @@ /* elision-unlock.c: Commit an elided pthread lock. - Copyright (C) 2015-2016 Free Software Foundation, Inc. + Copyright (C) 2015-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -23,18 +23,25 @@ int __lll_unlock_elision (int *lock, short *adapt_count, int pshared) { +#ifndef __SPE__ /* When the lock was free we're in a transaction. */ if (*lock == 0) __libc_tend (0); else { - lll_unlock ((*lock), pshared); + /* Update adapt_count in the critical section to prevent a + write-after-destroy error as mentioned in BZ 20822. The + following update of adapt_count has to be contained within + the critical region of the fall-back lock in order to not violate + the mutex destruction requirements. */ + short __tmp = atomic_load_relaxed (adapt_count); + if (__tmp > 0) + atomic_store_relaxed (adapt_count, __tmp - 1); - /* Update the adapt count AFTER completing the critical section. - Doing this here prevents unneeded stalling when entering - a critical section. Saving about 8% runtime on P8. */ - if (*adapt_count > 0) - (*adapt_count)--; + lll_unlock ((*lock), pshared); } +#else + lll_unlock ((*lock), pshared); +#endif return 0; } |