forked from luck/tmp_suning_uos_patched
perf/core: Disable page faults when getting phys address
We hit following warning when running tests on kernel compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y: WARNING: CPU: 19 PID: 4472 at mm/gup.c:2381 __get_user_pages_fast+0x1a4/0x200 CPU: 19 PID: 4472 Comm: dummy Not tainted 5.6.0-rc6+ #3 RIP: 0010:__get_user_pages_fast+0x1a4/0x200 ... Call Trace: perf_prepare_sample+0xff1/0x1d90 perf_event_output_forward+0xe8/0x210 __perf_event_overflow+0x11a/0x310 __intel_pmu_pebs_event+0x657/0x850 intel_pmu_drain_pebs_nhm+0x7de/0x11d0 handle_pmi_common+0x1b2/0x650 intel_pmu_handle_irq+0x17b/0x370 perf_event_nmi_handler+0x40/0x60 nmi_handle+0x192/0x590 default_do_nmi+0x6d/0x150 do_nmi+0x2f9/0x3c0 nmi+0x8e/0xd7 While __get_user_pages_fast() is IRQ-safe, it calls access_ok(), which warns on: WARN_ON_ONCE(!in_task() && !pagefault_disabled()) Peter suggested disabling page faults around __get_user_pages_fast(), which gets rid of the warning in access_ok() call. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200407141427.3184722-1-jolsa@kernel.org
This commit is contained in:
parent
2b3b76b5ec
commit
d3296fb372
|
@ -6934,9 +6934,12 @@ static u64 perf_virt_to_phys(u64 virt)
|
|||
* Try IRQ-safe __get_user_pages_fast first.
|
||||
* If failed, leave phys_addr as 0.
|
||||
*/
|
||||
if ((current->mm != NULL) &&
|
||||
(__get_user_pages_fast(virt, 1, 0, &p) == 1))
|
||||
phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
|
||||
if (current->mm != NULL) {
|
||||
pagefault_disable();
|
||||
if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
|
||||
phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
|
||||
pagefault_enable();
|
||||
}
|
||||
|
||||
if (p)
|
||||
put_page(p);
|
||||
|
|
Loading…
Reference in New Issue
Block a user