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hwpmc: set default rate if event description lacks one / filter rate against misuse

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Not all event descriptions have a sample rate (such as inst_retired.any)
this will restore the legacy behavior of using 65536 in that case. It also
prevents accidental API misuse that could lead to panic.

PR:	230985
Reported by:	markj
Reviewed by:	markj
Approved by:	re (gjb)
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D16958
This commit is contained in:
Matt Macy 2018-09-14 01:30:05 +00:00
parent 3b9156971f
commit 0204d85a62
2 changed files with 22 additions and 6 deletions
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1
lib/libpmc/libpmc_pmu_util.c
View File

@ -237,6 +237,7 @@ pmu_parse_event(struct pmu_event_desc *ped, const char *eventin)
return (ENOMEM);
r = event;
bzero(ped, sizeof(*ped));
ped->ped_period = DEFAULT_SAMPLE_COUNT;
ped->ped_umask = -1;
while ((kvp = strsep(&event, ",")) != NULL) {
key = strsep(&kvp, "=");

27
sys/dev/hwpmc/hwpmc_mod.c
View File

@ -61,6 +61,7 @@ __FBSDID("$FreeBSD$");
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/vnode.h>
@ -3942,9 +3943,16 @@ pmc_syscall_handler(struct thread *td, void *syscall_args)
pmc->pm_flags = pa.pm_flags;
/* XXX set lower bound on sampling for process counters */
if (PMC_IS_SAMPLING_MODE(mode))
pmc->pm_sc.pm_reloadcount = pa.pm_count;
else
if (PMC_IS_SAMPLING_MODE(mode)) {
/*
* Don't permit requested sample rate to be less than 1000
*/
if (pa.pm_count < 1000)
log(LOG_WARNING,
"pmcallocate: passed sample rate %ju - setting to 1000\n",
(uintmax_t)pa.pm_count);
pmc->pm_sc.pm_reloadcount = MAX(1000, pa.pm_count);
} else
pmc->pm_sc.pm_initial = pa.pm_count;
/* switch thread to CPU 'cpu' */
@ -4460,9 +4468,16 @@ pmc_syscall_handler(struct thread *td, void *syscall_args)
break;
}
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pm->pm_sc.pm_reloadcount = sc.pm_count;
else
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm))) {
/*
* Don't permit requested sample rate to be less than 1000
*/
if (sc.pm_count < 1000)
log(LOG_WARNING,
"pmcsetcount: passed sample rate %ju - setting to 1000\n",
(uintmax_t)sc.pm_count);
pm->pm_sc.pm_reloadcount = MAX(1000, sc.pm_count);
} else
pm->pm_sc.pm_initial = sc.pm_count;
}
break;