6:48 p.m.
On Wed, Apr 14, 2021 at 04:33:22PM +0200, Marco Elver wrote:
On Wed, Apr 14, 2021 at 10:10PM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git perf/core
> head: 0da503cd07380952599b67ded6efe030d78ea42d
> commit: c7d4112e9f0e69edd649665836ce72008b95ab9f [18/22] perf: Add support for
SIGTRAP on perf events
[...]
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp(a)intel.com>
[...]
> 6416 info.si_errno = event->attr.type;
> 6417 info.si_perf = event->attr.sig_data;
> > 6418 info.si_addr = (void *)event->sig_addr;
> 6419 force_sig_info(&info);
I think it wants the below (feel free to squash into "perf: Add support
for SIGTRAP on perf events").
Thanks,
-- Marco
------ >8 ------
From: Marco Elver <elver(a)google.com>
Date: Wed, 14 Apr 2021 16:26:26 +0200
Subject: [PATCH] perf: Fix cast to void __user pointer
sparse let us know that si_addr is 'void __user *', therefore add the
missing __user attribute to the cast.
Reported-by: kernel test robot <lkp(a)intel.com>
Signed-off-by: Marco Elver <elver(a)google.com>
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1d2077389c0c..2677438ed668 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6414,7 +6414,7 @@ static void perf_sigtrap(struct perf_event *event)
info.si_code = TRAP_PERF;
info.si_errno = event->attr.type;
info.si_perf = event->attr.sig_data;
- info.si_addr = (void *)event->sig_addr;
+ info.si_addr = (void __user *)event->sig_addr;
force_sig_info(&info);
}
Now the silly robot complains about:
CC kernel/events/core.o
../kernel/events/core.c: In function ‘perf_sigtrap’:
../kernel/events/core.c:6418:17: warning: cast to pointer from integer of different size
[-Wint-to-pointer-cast]
6418 | info.si_addr = (void __user *)event->sig_addr;
for all 32bit builds (because sig_addr is u64 and the pointer cast
truncates bits).
This had me look a little harder at sig_addr and I figured it should be
next to the pending fields for cache locality.
I've ended up with the below delta, does that work for you?
---
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -735,6 +735,7 @@ struct perf_event {
int pending_wakeup;
int pending_kill;
int pending_disable;
+ unsigned long pending_addr; /* SIGTRAP */
struct irq_work pending;
atomic_t event_limit;
@@ -778,9 +779,6 @@ struct perf_event {
void *security;
#endif
struct list_head sb_list;
-
- /* Address associated with event, which can be passed to siginfo_t. */
- u64 sig_addr;
#endif /* CONFIG_PERF_EVENTS */
};
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6415,7 +6415,7 @@ static void perf_sigtrap(struct perf_eve
info.si_code = TRAP_PERF;
info.si_errno = event->attr.type;
info.si_perf = event->attr.sig_data;
- info.si_addr = (void __user *)event->sig_addr;
+ info.si_addr = (void __user *)event->pending_addr;
force_sig_info(&info);
}
@@ -9137,7 +9137,7 @@ static int __perf_event_overflow(struct
if (events && atomic_dec_and_test(&event->event_limit)) {
ret = 1;
event->pending_kill = POLL_HUP;
- event->sig_addr = data->addr;
+ event->pending_addr = data->addr;
perf_event_disable_inatomic(event);
}