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.") Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann arnd@arndb.de --- As stated above, this was only found by inspection, the patch is not tested. Please review accordingly. --- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 787290781b8c..0d14f51d0002 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -3155,6 +3155,7 @@ 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