4.20-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
commit 5a9372f751b5350e0ce3d2ee91832f1feae2c2e5 upstream.
While reading through the sysvipc implementation, I noticed that the n32 semctl/shmctl/msgctl system calls behave differently based on whether o32 support is enabled or not: Without o32, the IPC_64 flag passed by user space is rejected but calls without that flag get IPC_64 behavior.
As far as I can tell, this was inadvertently changed by a cleanup patch but never noticed by anyone, possibly nobody has tried using sysvipc on n32 after linux-3.19.
Change it back to the old behavior now.
Fixes: 78aaf956ba3a ("MIPS: Compat: Fix build error if CONFIG_MIPS32_COMPAT but no compat ABI.") Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Paul Burton paul.burton@mips.com Cc: linux-mips@vger.kernel.org Cc: stable@vger.kernel.org # 3.19+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+)
--- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -3184,6 +3184,7 @@ config MIPS32_O32 config MIPS32_N32 bool "Kernel support for n32 binaries" depends on 64BIT + select ARCH_WANT_COMPAT_IPC_PARSE_VERSION select COMPAT select MIPS32_COMPAT select SYSVIPC_COMPAT if SYSVIPC