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authorChris Metcalf <cmetcalf@tilera.com>2013-03-04 11:19:09 -0500
committerChris Metcalf <cmetcalf@tilera.com>2013-03-04 11:19:09 -0500
commit5a114b98661e3aaa0ac085eb931584dce3b0ef9b (patch)
tree375a9103da9b40c1213d3bf78ed25f99c0df8455 /arch/tile
parent6dbe51c251a327e012439c4772097a13df43c5b8 (diff)
downloadlinux-5a114b98661e3aaa0ac085eb931584dce3b0ef9b.tar.gz
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]
Diffstat (limited to 'arch/tile')
-rw-r--r--arch/tile/include/asm/compat.h3
-rw-r--r--arch/tile/kernel/compat.c13
2 files changed, 16 insertions, 0 deletions
diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h
index 001d418a895..78f1f2ded86 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 7f72401b4f4..69034e21574 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