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Commit 859d880c authored Mar 06, 2018 by Eric W. Biederman

signal: Correct the offset of si_pkey in struct siginfo



The change moving addr_lsb into the _sigfault union failed to take
into account that _sigfault._addr_bnd._lower being a pointer forced
the entire union to have pointer alignment.  In practice this only
mattered for the offset of si_pkey which is why this has taken so long
to discover.

To correct this change _dummy_pkey and _dummy_bnd to have pointer type.

Reported-by: kernel test robot <shun.hao@intel.com>
Fixes: b68a68d3 ("signal: Move addr_lsb into the _sigfault union for clarity")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent 9026e820

include/linux/compat.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -229,13 +229,13 @@ typedef struct compat_siginfo {
		short int _addr_lsb; /* Valid LSB of the reported address. */
		/* used when si_code=SEGV_BNDERR */
		struct {
		short _dummy_bnd;
		compat_uptr_t _dummy_bnd;
		compat_uptr_t _lower;
		compat_uptr_t _upper;
		} _addr_bnd;
		/* used when si_code=SEGV_PKUERR */
		struct {
		short _dummy_pkey;
		compat_uptr_t _dummy_pkey;
		u32 _pkey;
		} _addr_pkey;
		};

include/uapi/asm-generic/siginfo.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -102,13 +102,13 @@ typedef struct siginfo {
		short _addr_lsb; /* LSB of the reported address */
		/* used when si_code=SEGV_BNDERR */
		struct {
		short _dummy_bnd;
		void *_dummy_bnd;
		void __user *_lower;
		void __user *_upper;
		} _addr_bnd;
		/* used when si_code=SEGV_PKUERR */
		struct {
		short _dummy_pkey;
		void *_dummy_pkey;
		__u32 _pkey;
		} _addr_pkey;
		};