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Tidy up pmc support at execve.

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The proc-specific check is inherently racy, so the code can just unlock
beforehand.

MFC after:	1 week
This commit is contained in:
Mateusz Guzik 2017-10-19 00:38:14 +00:00
parent cb1c79008e
commit 80a2397a38
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=324734
1 changed files with 3 additions and 8 deletions
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11
sys/kern/kern_exec.c
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@ -849,28 +849,23 @@ do_execve(struct thread *td, struct image_args *args, struct mac *mac_p)
p->p_args = newargs;
newargs = NULL;
PROC_UNLOCK(p);
#ifdef HWPMC_HOOKS
/*
* Check if system-wide sampling is in effect or if the
* current process is using PMCs. If so, do exec() time
* processing. This processing needs to happen AFTER the
* P_INEXEC flag is cleared.
*
* The proc lock needs to be released before taking the PMC
* SX.
*/
if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
PROC_UNLOCK(p);
VOP_UNLOCK(imgp->vp, 0);
pe.pm_credentialschanged = credential_changing;
pe.pm_entryaddr = imgp->entry_addr;
PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
} else
PROC_UNLOCK(p);
#else /* !HWPMC_HOOKS */
PROC_UNLOCK(p);
}
#endif
/* Set values passed into the program in registers. */