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| author | Andy Lutomirski <luto@kernel.org> | 2015-07-31 00:31:32 +0300 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2016-03-21 04:17:50 +0300 |
| commit | 0444d9dfacb4fa42005ca3afefe56b16f07c5192 (patch) | |
| tree | 53d1607b454192c2d01fdb09a8fbc68fd27e7991 /arch/x86/power/cpu.c | |
| parent | 86462c4a7b54e8ae93c9e46d80b9d404f707eca2 (diff) | |
| download | linux-0444d9dfacb4fa42005ca3afefe56b16f07c5192.tar.xz | |
x86/ldt: Make modify_ldt synchronous
commit 37868fe113ff2ba814b3b4eb12df214df555f8dc upstream.
modify_ldt() has questionable locking and does not synchronize
threads. Improve it: redesign the locking and synchronize all
threads' LDTs using an IPI on all modifications.
This will dramatically slow down modify_ldt in multithreaded
programs, but there shouldn't be any multithreaded programs that
care about modify_ldt's performance in the first place.
This fixes some fallout from the CVE-2015-5157 fixes.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org <security@kernel.org>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/4c6978476782160600471bd865b318db34c7b628.1438291540.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2:
- Adjust context
- Drop comment changes in switch_mm()
- Drop changes to get_segment_base() in arch/x86/kernel/cpu/perf_event.c
- Open-code lockless_dereference(), smp_store_release(), on_each_cpu_mask()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'arch/x86/power/cpu.c')
| -rw-r--r-- | arch/x86/power/cpu.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index fcbaac60d938..dd298e73cbb3 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -22,6 +22,7 @@ #include <asm/suspend.h> #include <asm/debugreg.h> #include <asm/fpu-internal.h> /* pcntxt_mask */ +#include <asm/mmu_context.h> #ifdef CONFIG_X86_32 static struct saved_context saved_context; @@ -148,7 +149,7 @@ static void fix_processor_context(void) syscall_init(); /* This sets MSR_*STAR and related */ #endif load_TR_desc(); /* This does ltr */ - load_LDT(¤t->active_mm->context); /* This does lldt */ + load_mm_ldt(current->active_mm); /* This does lldt */ } /** |