Andrea Parri 09d3f015d1 uprobes: Fix handle_swbp() vs. unregister() + register() race once more ... Commit: 142b18ddc8 ("uprobes: Fix handle_swbp() vs unregister() + register() race") added the UPROBE_COPY_INSN flag, and corresponding smp_wmb() and smp_rmb() memory barriers, to ensure that handle_swbp() uses fully-initialized uprobes only. However, the smp_rmb() is mis-placed: this barrier should be placed after handle_swbp() has tested for the flag, thus guaranteeing that (program-order) subsequent loads from the uprobe can see the initial stores performed by prepare_uprobe(). Move the smp_rmb() accordingly. Also amend the comments associated to the two memory barriers to indicate their actual locations. Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: stable@kernel.org Fixes: 142b18ddc8 ("uprobes: Fix handle_swbp() vs unregister() + register() race") Link: http://lkml.kernel.org/r/20181122161031.15179-1-andrea.parri@amarulasolutions.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2018-11-23 08:31:19 +01:00
..
callchain.c	treewide: convert ISO_8859-1 text comments to utf-8	2018-08-23 18:48:43 -07:00
core.c	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2018-11-03 18:13:43 -07:00
hw_breakpoint.c	perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint	2018-08-30 14:49:23 -03:00
internal.h	perf: Make perf_callchain function static	2018-01-08 12:33:01 -03:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
ring_buffer.c	perf: Suppress AUX/OVERWRITE records	2018-09-18 17:21:13 -03:00
uprobes.c	uprobes: Fix handle_swbp() vs. unregister() + register() race once more	2018-11-23 08:31:19 +01:00