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authorSiddha, Suresh B <suresh.b.siddha@intel.com>2007-10-19 20:35:02 +0200
committerThomas Gleixner <tglx@linutronix.de>2007-10-19 20:35:02 +0200
commit957ff882f9db86e017f730e77322ec5193178e5e (patch)
tree4db49853a5191bf8a91825ac50125f8b411ce4ea
parentf322727b92957ccd4b0366dbd42908613222033a (diff)
x86, vsyscall: fix the oops crash with __pa_vsymbol()
Appended patch fixes an oops while changing the vsyscall sysctl. I am sure no one tested this code before integrating into mainline :( BTW, using ioremap() in vsyscall_sysctl_change() to get the virtual address of a kernel symbol sounds like an over kill.. I wonder if we can define a simple __va_vsymbol() which will return directly the kernel direct mapping. comments in the code which says gcc has trouble with __va(__pa()) sounds bogus to me. __pa() on a vsyscall address will not work anyhow :( And also, the whole nop out syscall in vsyscall page infrastructure (vsyscall_sysctl_change()) is added to make some attacks difficult, and yet I don't see this nop out being done by default. This area requires more cleanups? Fix an oops with __pa_vsymbol(). VSYSCALL_FIRST_PAGE is a fixmap index. We want the starting virtual address of the vsyscall page and not the index. [ mingo: arch/x86 adaptation ] Reported-by: Yanmin Zhang <yanmin.zhang@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/kernel/vsyscall_64.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 585541ca1a7..4a2c340ab0f 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -48,7 +48,7 @@
({unsigned long v; \
extern char __vsyscall_0; \
asm("" : "=r" (v) : "0" (x)); \
- ((v - VSYSCALL_FIRST_PAGE) + __pa_symbol(&__vsyscall_0)); })
+ ((v - VSYSCALL_START) + __pa_symbol(&__vsyscall_0)); })
/*
* vsyscall_gtod_data contains data that is :