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authorAlexey Dobriyan <adobriyan@gmail.com>2023-01-06 22:30:14 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-01-11 16:14:22 -0800
commit5316a017d093f644675a56523bcf5787ba8f4fef (patch)
treea4724f87f50fe6acc553fac0da04cab0808a29bb /tools/testing
parent8651a137e62ebfde3df95cbb1ca055d013ec5b9e (diff)
proc: fix PIE proc-empty-vm, proc-pid-vm tests
vsyscall detection code uses direct call to the beginning of the vsyscall page: asm ("call %P0" :: "i" (0xffffffffff600000)) It generates "call rel32" instruction but it is not relocated if binary is PIE, so binary segfaults into random userspace address and vsyscall page status is detected incorrectly. Do more direct: asm ("call *%rax") which doesn't do need any relocaltions. Mark g_vsyscall as volatile for a good measure, I didn't find instruction setting it to 0. Now the code is obviously correct: xor eax, eax mov rdi, rbp mov rsi, rbp mov DWORD PTR [rip+0x2d15], eax # g_vsyscall = 0 mov rax, 0xffffffffff600000 call rax mov DWORD PTR [rip+0x2d02], 1 # g_vsyscall = 1 mov eax, DWORD PTR ds:0xffffffffff600000 mov DWORD PTR [rip+0x2cf1], 2 # g_vsyscall = 2 mov edi, [rip+0x2ceb] # exit(g_vsyscall) call exit Note: fixed proc-empty-vm test oopses 5.19.0-28-generic kernel but this is separate story. Link: https://lkml.kernel.org/r/Y7h2xvzKLg36DSq8@p183 Fixes: 5bc73bb3451b9 ("proc: test how it holds up with mapping'less process") Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> Tested-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools/testing')
-rw-r--r--tools/testing/selftests/proc/proc-empty-vm.c12
-rw-r--r--tools/testing/selftests/proc/proc-pid-vm.c9
2 files changed, 12 insertions, 9 deletions
diff --git a/tools/testing/selftests/proc/proc-empty-vm.c b/tools/testing/selftests/proc/proc-empty-vm.c
index d95b1cb43d9d..7588428b8fcd 100644
--- a/tools/testing/selftests/proc/proc-empty-vm.c
+++ b/tools/testing/selftests/proc/proc-empty-vm.c
@@ -25,6 +25,7 @@
#undef NDEBUG
#include <assert.h>
#include <errno.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -41,7 +42,7 @@
* 1: vsyscall VMA is --xp vsyscall=xonly
* 2: vsyscall VMA is r-xp vsyscall=emulate
*/
-static int g_vsyscall;
+static volatile int g_vsyscall;
static const char *g_proc_pid_maps_vsyscall;
static const char *g_proc_pid_smaps_vsyscall;
@@ -147,11 +148,12 @@ static void vsyscall(void)
g_vsyscall = 0;
/* gettimeofday(NULL, NULL); */
+ uint64_t rax = 0xffffffffff600000;
asm volatile (
- "call %P0"
- :
- : "i" (0xffffffffff600000), "D" (NULL), "S" (NULL)
- : "rax", "rcx", "r11"
+ "call *%[rax]"
+ : [rax] "+a" (rax)
+ : "D" (NULL), "S" (NULL)
+ : "rcx", "r11"
);
g_vsyscall = 1;
diff --git a/tools/testing/selftests/proc/proc-pid-vm.c b/tools/testing/selftests/proc/proc-pid-vm.c
index 69551bfa215c..cacbd2a4aec9 100644
--- a/tools/testing/selftests/proc/proc-pid-vm.c
+++ b/tools/testing/selftests/proc/proc-pid-vm.c
@@ -257,11 +257,12 @@ static void vsyscall(void)
g_vsyscall = 0;
/* gettimeofday(NULL, NULL); */
+ uint64_t rax = 0xffffffffff600000;
asm volatile (
- "call %P0"
- :
- : "i" (0xffffffffff600000), "D" (NULL), "S" (NULL)
- : "rax", "rcx", "r11"
+ "call *%[rax]"
+ : [rax] "+a" (rax)
+ : "D" (NULL), "S" (NULL)
+ : "rcx", "r11"
);
g_vsyscall = 1;