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nptl: Add EOVERFLOW checks for futex calls

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Some futex-internal calls require additional check for EOVERFLOW (as
indicated by [1] [2] [3]).  For both mutex and rwlock code, EOVERFLOW is
handle as ETIMEDOUT; since it indicate to the caller that the blocking
operation could not be issued.

For mutex it avoids a possible issue where PTHREAD_MUTEX_ROBUST_* might
assume EOVERFLOW indicate futex has succeed, and for PTHREAD_MUTEX_PP_*
it avoid a potential busy infinite loop.  For rwlock and semaphores, it
also avoids potential busy infinite loops.

Checked on x86_64-linux-gnu and i686-linux-gnu, although EOVERFLOW
won't be possible with current usage (since all timeouts on 32-bit
architectures with 32-bit time_t support will be in the range of
32-bit time_t).

[1] https://sourceware.org/pipermail/libc-alpha/2020-November/120079.html
[2] https://sourceware.org/pipermail/libc-alpha/2020-November/120080.html
[3] https://sourceware.org/pipermail/libc-alpha/2020-November/120127.html
This commit is contained in:
Adhemerval Zanella
2020-11-26 10:54:04 -03:00
parent 71eeae0325
commit aa69f19a93
4 changed files with 13 additions and 13 deletions
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4
nptl/pthread_cond_wait.c
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@@ -506,7 +506,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
__pthread_cleanup_pop (&buffer, 0);
if (__glibc_unlikely (err == ETIMEDOUT))
if (__glibc_unlikely (err == ETIMEDOUT || err == EOVERFLOW))
{
__condvar_dec_grefs (cond, g, private);
/* If we timed out, we effectively cancel waiting. Note that
@@ -515,7 +515,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
__condvar_quiesce_and_switch_g1 and us trying to acquire
the lock during cancellation is not possible. */
__condvar_cancel_waiting (cond, seq, g, private);
result = ETIMEDOUT;
result = err;
goto done;
}
else