Messages in this thread Patch in this message | | | From | Denys Vlasenko <> | Subject | [PATCH] x86/asm/entry/32: Fix fallout from r9 trick removal in SYSCALL code | Date | Tue, 9 Jun 2015 19:25:53 +0200 |
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I put %ebp restoration code too late. Under strace, it is not reached and %ebp is not restored upon return to userspace.
This is the fix. Run-tested.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Steven Rostedt <rostedt@goodmis.org> CC: Ingo Molnar <mingo@kernel.org> CC: Borislav Petkov <bp@alien8.de> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Alexei Starovoitov <ast@plumgrid.com> CC: Will Drewry <wad@chromium.org> CC: Kees Cook <keescook@chromium.org> CC: x86@kernel.org CC: linux-kernel@vger.kernel.org --- arch/x86/entry/entry_64_compat.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 2093ce6..2c44180 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -344,6 +344,7 @@ cstar_dispatch: call *ia32_sys_call_table(, %rax, 8) movq %rax, RAX(%rsp) 1: + movl RCX(%rsp), %ebp DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) @@ -351,7 +352,6 @@ cstar_dispatch: sysretl_from_sys_call: andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) - movl RCX(%rsp), %ebp RESTORE_RSI_RDI_RDX movl RIP(%rsp), %ecx movl EFLAGS(%rsp), %r11d -- 1.8.1.4
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