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perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint

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Currently we enable the breakpoint back only if the breakpoint
modification was successful. If it fails we can leave the breakpoint in
disabled state with attr->disabled == 0.

We can safely enable the breakpoint back for both the fail and success
paths by checking the bp->attr.disabled, which either holds the new
'requested' disabled state or the original breakpoint state.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-5-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2018-08-27 11:12:27 +02:00 committed by Arnaldo Carvalho de Melo
parent cb45302d7c
commit 969558371b
1 changed files with 2 additions and 4 deletions
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6
kernel/events/hw_breakpoint.c
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@ -523,13 +523,11 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
perf_event_disable(bp); perf_event_disable(bp);
err = modify_user_hw_breakpoint_check(bp, attr, false); err = modify_user_hw_breakpoint_check(bp, attr, false);
if (err)
return err;
if (!attr->disabled) if (!bp->attr.disabled)
perf_event_enable(bp); perf_event_enable(bp);
return 0; return err;
} }
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);