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Date:   Thu, 22 Apr 2021 08:44:37 +0200
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Subject: [PATCH tip 2/2] signal, perf: Add missing TRAP_PERF case in siginfo_layout()
From:   Marco Elver <elver@google.com>
To:     elver@google.com, peterz@infradead.org, mingo@redhat.com,
        tglx@linutronix.de
Cc:     m.szyprowski@samsung.com, jonathanh@nvidia.com, dvyukov@google.com,
        glider@google.com, arnd@arndb.de, christian@brauner.io,
        axboe@kernel.dk, pcc@google.com, oleg@redhat.com,
        kasan-dev@googlegroups.com, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
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Add the missing TRAP_PERF case in siginfo_layout() for interpreting the
layout correctly as SIL_PERF_EVENT instead of just SIL_FAULT. This
ensures the si_perf field is copied and not just the si_addr field.

This was caught and tested by running the perf_events/sigtrap_threads
kselftest as a 32-bit binary with a 64-bit kernel.

Fixes: fb6cc127e0b6 ("signal: Introduce TRAP_PERF si_code and si_perf to siginfo")
Signed-off-by: Marco Elver <elver@google.com>
---
 kernel/signal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/signal.c b/kernel/signal.c
index 9ed81ee4ff17..b354655a0e57 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3251,6 +3251,8 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
 			else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
 				layout = SIL_FAULT_PKUERR;
 #endif
+			else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
+				layout = SIL_PERF_EVENT;
 		}
 		else if (si_code <= NSIGPOLL)
 			layout = SIL_POLL;
-- 
2.31.1.498.g6c1eba8ee3d-goog