We soon won't be able to rely on bp->attr anymore to get the new type of the modifying breakpoint because the new attributes are going to be copied only once we successfully modified the breakpoint slot.
This will fix the current misdesigned layout where the new attr are copied to the modifying breakpoint before we actually know if the modification will be validated. In order to prepare for that, allow modify_breakpoint_slot() to take the new breakpoint type. Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Yoshinori Sato <[email protected]> Cc: Rich Felker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Will Deacon <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Max Filippov <[email protected]> Cc: Chris Zankel <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Joel Fernandes <[email protected]> --- kernel/events/hw_breakpoint.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index e7bc8d0..7138770 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -345,13 +345,13 @@ void release_bp_slot(struct perf_event *bp) mutex_unlock(&nr_bp_mutex); } -static int __modify_bp_slot(struct perf_event *bp, u64 old_type) +static int __modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) { int err; __release_bp_slot(bp, old_type); - err = __reserve_bp_slot(bp, bp->attr.bp_type); + err = __reserve_bp_slot(bp, new_type); if (err) { /* * Reserve the old_type slot back in case @@ -367,12 +367,12 @@ static int __modify_bp_slot(struct perf_event *bp, u64 old_type) return err; } -static int modify_bp_slot(struct perf_event *bp, u64 old_type) +static int modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) { int ret; mutex_lock(&nr_bp_mutex); - ret = __modify_bp_slot(bp, old_type); + ret = __modify_bp_slot(bp, old_type, new_type); mutex_unlock(&nr_bp_mutex); return ret; } @@ -481,7 +481,7 @@ modify_user_hw_breakpoint_check(struct perf_event *bp, struct perf_event_attr *a err = hw_breakpoint_parse(bp, attr, &hw); if (!err && modify) - err = modify_bp_slot(bp, old_type); + err = modify_bp_slot(bp, old_type, bp->attr.bp_type); if (err) { bp->attr.bp_addr = old_addr; -- 2.7.4
