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| author | Chris Metcalf <cmetcalf@tilera.com> | 2013-03-04 20:19:09 +0400 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@tilera.com> | 2013-03-04 20:19:09 +0400 |
| commit | 5a114b98661e3aaa0ac085eb931584dce3b0ef9b (patch) | |
| tree | 375a9103da9b40c1213d3bf78ed25f99c0df8455 | |
| parent | 6dbe51c251a327e012439c4772097a13df43c5b8 (diff) | |
| download | linux-5a114b98661e3aaa0ac085eb931584dce3b0ef9b.tar.xz | |
tile: work around bug in the generic sys_llseek
sys_llseek should specify the high and low 32-bit seek values as "unsigned
int" but instead it specifies "unsigned long". Since compat syscall
arguments are always sign-extended on tile, this means that a seek value
of 0xffffffff will be incorrectly interpreted as a value of -1ULL.
To avoid the risk of breaking binary compatibility on architectures
that already use sys_llseek this way, we follow the same path as MIPS
and provide a wrapper override.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: stable@kernel.org [v3.6 onwards]
| -rw-r--r-- | arch/tile/include/asm/compat.h | 3 | ||||
| -rw-r--r-- | arch/tile/kernel/compat.c | 13 |
2 files changed, 16 insertions, 0 deletions
diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h index 001d418a8957..78f1f2ded86c 100644 --- a/arch/tile/include/asm/compat.h +++ b/arch/tile/include/asm/compat.h @@ -288,6 +288,9 @@ long compat_sys_sync_file_range2(int fd, unsigned int flags, long compat_sys_fallocate(int fd, int mode, u32 offset_lo, u32 offset_hi, u32 len_lo, u32 len_hi); +long compat_sys_llseek(unsigned int fd, unsigned int offset_high, + unsigned int offset_low, loff_t __user * result, + unsigned int origin); /* Assembly trampoline to avoid clobbering r0. */ long _compat_sys_rt_sigreturn(void); diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c index 7f72401b4f45..69034e215742 100644 --- a/arch/tile/kernel/compat.c +++ b/arch/tile/kernel/compat.c @@ -76,6 +76,18 @@ long compat_sys_fallocate(int fd, int mode, ((loff_t)len_hi << 32) | len_lo); } +/* + * Avoid bug in generic sys_llseek() that specifies offset_high and + * offset_low as "unsigned long", thus making it possible to pass + * a sign-extended high 32 bits in offset_low. + */ +long compat_sys_llseek(unsigned int fd, unsigned int offset_high, + unsigned int offset_low, loff_t __user * result, + unsigned int origin) +{ + return sys_llseek(fd, offset_high, offset_low, result, origin); +} + /* Provide the compat syscall number to call mapping. */ #undef __SYSCALL #define __SYSCALL(nr, call) [nr] = (call), @@ -83,6 +95,7 @@ long compat_sys_fallocate(int fd, int mode, /* See comments in sys.c */ #define compat_sys_fadvise64_64 sys32_fadvise64_64 #define compat_sys_readahead sys32_readahead +#define sys_llseek compat_sys_llseek /* Call the assembly trampolines where necessary. */ #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn |