linux-stable/kernel/events
Greg Thelen 4716023a8f perf/core: Avoid put_page() when GUP fails
PEBS PERF_SAMPLE_PHYS_ADDR events use perf_virt_to_phys() to convert PMU
sampled virtual addresses to physical using get_user_page_fast_only()
and page_to_phys().

Some get_user_page_fast_only() error cases return false, indicating no
page reference, but still initialize the output page pointer with an
unreferenced page. In these error cases perf_virt_to_phys() calls
put_page(). This causes page reference count underflow, which can lead
to unintentional page sharing.

Fix perf_virt_to_phys() to only put_page() if get_user_page_fast_only()
returns a referenced page.

Fixes: fc7ce9c74c ("perf/core, x86: Add PERF_SAMPLE_PHYS_ADDR")
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211111021814.757086-1-gthelen@google.com
2021-11-11 13:09:34 +01:00
..
Makefile perf/core: allow ftrace for functions in kernel/event/core.c 2021-10-25 22:50:42 -04:00
callchain.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
core.c perf/core: Avoid put_page() when GUP fails 2021-11-11 13:09:34 +01:00
hw_breakpoint.c perf/hw_breakpoint: Replace deprecated CPU-hotplug functions 2021-08-26 09:14:36 +02:00
internal.h tracing/perf: Add interrupt_context_level() helper 2021-10-19 20:33:20 -04:00
ring_buffer.c perf: Cap allocation order at aux_watermark 2021-04-16 16:32:39 +02:00
uprobes.c mm/memcg: Convert mem_cgroup_charge() to take a folio 2021-09-27 09:27:31 -04:00