Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH] tty/sysrq: Make local variable 'killer' in sysrq_handle_crash() global | Date | Tue, 18 Sep 2018 11:46:30 +0000 |
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From: Matthias Kaehlcke > Sent: 17 September 2018 22:33 > > sysrq_handle_crash() dereferences a NULL pointer on purpose to force > an exception, the local variable 'killer' is assigned to NULL and > dereferenced later. Clang detects the NULL pointer dereference at compile > time and emits a BRK instruction (on arm64) instead of the expected NULL > pointer exception. Change 'killer' to a global variable (and rename it > to 'sysrq_killer' to avoid possible clashes) to prevent Clang from > detecting the condition. By default global variables are initialized > with zero/NULL in C, therefore an explicit initialization is not needed.
You need an explicit initialiser in order to make it global data rather than a common section.
David
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