Greg Thelen bd40513d0b perf/core: Avoid put_page() when GUP fails ... commit 4716023a8f6a0f4a28047f14dd7ebdc319606b84 upstream. 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 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-11-21 13:46:37 +01:00
..
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	2021-11-21 13:46:37 +01:00
hw_breakpoint.c
internal.h	perf: Optimize get_recursion_context()	2020-11-09 18:12:34 +01:00
Makefile
ring_buffer.c	perf: Reduce stack usage of perf_output_begin()	2020-11-09 18:12:33 +01:00
uprobes.c	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00