From 6ae1756faddefd7494353380ee546dd38c2f97eb Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 20 Feb 2018 15:44:37 +0000 Subject: [PATCH] MIPS: Drop spurious __unused in struct compat_flock MIPS' struct compat_flock doesn't match the 32-bit struct flock, as it has an extra short __unused before pad[4], which combined with alignment increases the size to 40 bytes compared with struct flock's 36 bytes. Since commit 8c6657cb50cb ("Switch flock copyin/copyout primitives to copy_{from,to}_user()"), put_compat_flock() writes the full compat_flock struct to userland, which results in corruption of the userland word after the struct flock when running 32-bit userlands on 64-bit kernels. This was observed to cause a bus error exception when starting Firefox on Debian 8 (Jessie). Reported-by: Peter Mamonov Signed-off-by: James Hogan Tested-by: Peter Mamonov Cc: Ralf Baechle Cc: Al Viro Cc: linux-mips@linux-mips.org Cc: # 4.13+ Patchwork: https://patchwork.linux-mips.org/patch/18646/ --- arch/mips/include/asm/compat.h | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h index 946681db8dc3..9a0fa66b81ac 100644 --- a/arch/mips/include/asm/compat.h +++ b/arch/mips/include/asm/compat.h @@ -86,7 +86,6 @@ struct compat_flock { compat_off_t l_len; s32 l_sysid; compat_pid_t l_pid; - short __unused; s32 pad[4]; }; -- 2.30.2