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 <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Jiri Olsa <[email protected]>
---
 kernel/events/hw_breakpoint.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 3e560d7609fd..d6b56180827c 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -523,13 +523,11 @@ int modify_user_hw_breakpoint(struct perf_event *bp, 
struct perf_event_attr *att
                perf_event_disable(bp);
 
        err = modify_user_hw_breakpoint_check(bp, attr, false);
-       if (err)
-               return err;
 
-       if (!attr->disabled)
+       if (!bp->attr.disabled)
                perf_event_enable(bp);
 
-       return 0;
+       return err;
 }
 EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
 
-- 
2.17.1

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