ppc64 sys_ipc breakage in 2.6.34-rc2

45575f5a · Anton Blanchard <[email protected]> · 2010-03-22 17:47:59 +11:00

I chased down a fail on ppc64 on 2.6.34-rc2 where an application that
uses shared memory was getting a SEGV.

Commit baed7fc9b580bd3fb8252ff1d9b36eaf1f86b670 ("Add generic sys_ipc
wrapper") changed the second argument from an unsigned long to an int.
When we call shmget the system call wrappers for sys_ipc will sign
extend second (ie the size) which truncates it.  It took a while to
track down because the call succeeds and strace shows the untruncated
size :)

The patch below changes second from an int to an unsigned long which
fixes shmget on ppc64 (and I assume s390, sparc64 and mips64).

Signed-off-by: Anton Blanchard <[email protected]>
--

I assume the function prototypes for the other IPC methods would cause us
to sign or zero extend second where appropriate (avoiding any security
issues). Come to think of it, the syscall wrappers for each method should do
that for us as well.
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 45575f5a426c01ec68cd33d998267ba2f6278fac
Parents: a90110c6

Changes

1 files changed · +1 −1

File	Status	Add	Del	Content
ipc/syscall.c	modified	+1	−1	View file

ipc/syscall.c

View file

diff --git a/ipc/syscall.c b/ipc/syscall.c
index 355a3da..1d6f53f 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -13,7 +13,7 @@
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 
-SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, int, second,
+SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
 		unsigned long, third, void __user *, ptr, long, fifth)
 {
 	int version, ret;