Gitweb:
http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=386fbf8e0d3082...
Commit: 386fbf8e0d30823854ffefb1b4e3b47b09ec5905
Parent: 081e406d0d0c02d8fb6f93d6b8fb97f4217fde62
Author: Zdenek Kabelac <zkabelac(a)redhat.com>
AuthorDate: Fri Sep 19 11:04:36 2014 +0200
Committer: Zdenek Kabelac <zkabelac(a)redhat.com>
CommitterDate: Fri Sep 19 15:55:47 2014 +0200
debug: enhance mmap catch code
Use nice instruction_HLT macro
Use log_debug_mem()
Don't actually log things after we prohibit 'mmap'.
Move initialization of strerror & udev before blocking mmap.
---
lib/mm/memlock.c | 29 ++++++++++++-----------------
1 files changed, 12 insertions(+), 17 deletions(-)
diff --git a/lib/mm/memlock.c b/lib/mm/memlock.c
index 0658800..37d9457 100644
--- a/lib/mm/memlock.c
+++ b/lib/mm/memlock.c
@@ -334,6 +334,7 @@ static int _memlock_maps(struct cmd_context *cmd, lvmlock_t lock,
size_t *mstats
#define _GNU_SOURCE
#endif
#include <dlfcn.h>
+static const unsigned char INSTRUCTION_HLT = 0x94;
static char _mmap_orig;
static unsigned char *_mmap_addr;
#ifdef __i386__
@@ -358,7 +359,7 @@ static int _disable_mmap(void)
#endif /* __i386__ */
_mmap_addr = *(void **)abs_addr;
} else
- log_debug("Can't find PLT jump entry assuming -fPIE linkage.");
+ log_debug_mem("Can't find PLT jump entry assuming -fPIE linkage.");
if (mprotect((void *)((unsigned long)_mmap_addr & ~4095UL), 4096,
PROT_READ|PROT_WRITE|PROT_EXEC)) {
log_sys_error("mprotect", "");
_mmap_addr = NULL;
@@ -366,8 +367,8 @@ static int _disable_mmap(void)
}
_mmap_orig = *_mmap_addr;
}
- *_mmap_addr = 0xf4;
- log_debug("Remapped mmap jump entry %x to %x.", _mmap_orig, *_mmap_addr);
+ log_debug_mem("Remapping mmap entry %02x to %02x.", _mmap_orig,
INSTRUCTION_HLT);
+ *_mmap_addr = INSTRUCTION_HLT;
#ifdef __i386__
if (!_mmap64_addr) {
@@ -375,8 +376,7 @@ static int _disable_mmap(void)
if (_mmap64_addr[0] == 0xff && _mmap64_addr[1] == 0x25) {
abs_addr = *(void **)(_mmap64_addr + 2);
_mmap64_addr = *(void **)abs_addr;
- } else
- log_debug("Can't find PLT jump entry assuming -fPIE linkage.");
+ } /* Can't find PLT jump entry assuming -fPIE linkage */
if (mprotect((void *)((unsigned long)_mmap64_addr & ~4095UL), 4096,
PROT_READ|PROT_WRITE|PROT_EXEC)) {
log_sys_error("mprotect", "");
_mmap64_addr = NULL;
@@ -384,8 +384,7 @@ static int _disable_mmap(void)
}
_mmap64_orig = *_mmap64_addr;
}
- *_mmap64_addr = 0xf4;
- log_debug("Remapped mmap64 jump entry %x to %x.", _mmap64_orig,
*_mmap64_addr);
+ *_mmap64_addr = INSTRUCTION_HLT;
#endif /* __i386__ */
#endif /* ARCH_X86 */
return 1;
@@ -394,16 +393,13 @@ static int _disable_mmap(void)
static int _restore_mmap(void)
{
#ifdef ARCH_X86
- if (_mmap_addr) {
- log_debug("Restoring mmap jump entry.");
+ if (_mmap_addr)
*_mmap_addr = _mmap_orig;
- }
#ifdef __i386__
- if (_mmap64_addr) {
- log_debug("Restoring mmap64 jump entry.");
+ if (_mmap64_addr)
*_mmap64_addr = _mmap64_orig;
- }
#endif /* __i386__ */
+ log_debug_mem("Restored mmap entry.");
#endif /* ARCH_X86 */
return 1;
}
@@ -412,6 +408,9 @@ static int _restore_mmap(void)
static void _lock_mem(struct cmd_context *cmd)
{
_allocate_memory();
+ (void)strerror(0); /* Force libc.mo load */
+ (void)dm_udev_get_sync_support(); /* udev is initialized */
+ log_very_verbose("Locking memory");
/*
* For daemon we need to use mlockall()
@@ -439,10 +438,6 @@ static void _lock_mem(struct cmd_context *cmd)
stack;
}
- (void)strerror(0); /* Force libc.mo load */
- (void)dm_udev_get_sync_support(); /* udev is initialized */
-
- log_very_verbose("Locking memory");
if (!_memlock_maps(cmd, LVM_MLOCK, &_mstats))
stack;