diff options
Diffstat (limited to 'arch/arm64/kernel/probes/decode-insn.c')
-rw-r--r-- | arch/arm64/kernel/probes/decode-insn.c | 48 |
1 files changed, 23 insertions, 25 deletions
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index 37e47a9d617e..d1731bf977ef 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -16,6 +16,7 @@ #include <linux/kernel.h> #include <linux/kprobes.h> #include <linux/module.h> +#include <linux/kallsyms.h> #include <asm/kprobes.h> #include <asm/insn.h> #include <asm/sections.h> @@ -122,7 +123,7 @@ arm_probe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) static bool __kprobes is_probed_address_atomic(kprobe_opcode_t *scan_start, kprobe_opcode_t *scan_end) { - while (scan_start > scan_end) { + while (scan_start >= scan_end) { /* * atomic region starts from exclusive load and ends with * exclusive store. @@ -142,33 +143,30 @@ arm_kprobe_decode_insn(kprobe_opcode_t *addr, struct arch_specific_insn *asi) { enum kprobe_insn decoded; kprobe_opcode_t insn = le32_to_cpu(*addr); - kprobe_opcode_t *scan_start = addr - 1; - kprobe_opcode_t *scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE; -#if defined(CONFIG_MODULES) && defined(MODULES_VADDR) - struct module *mod; -#endif - - if (addr >= (kprobe_opcode_t *)_text && - scan_end < (kprobe_opcode_t *)_text) - scan_end = (kprobe_opcode_t *)_text; -#if defined(CONFIG_MODULES) && defined(MODULES_VADDR) - else { - preempt_disable(); - mod = __module_address((unsigned long)addr); - if (mod && within_module_init((unsigned long)addr, mod) && - !within_module_init((unsigned long)scan_end, mod)) - scan_end = (kprobe_opcode_t *)mod->init_layout.base; - else if (mod && within_module_core((unsigned long)addr, mod) && - !within_module_core((unsigned long)scan_end, mod)) - scan_end = (kprobe_opcode_t *)mod->core_layout.base; - preempt_enable(); + kprobe_opcode_t *scan_end = NULL; + unsigned long size = 0, offset = 0; + + /* + * If there's a symbol defined in front of and near enough to + * the probe address assume it is the entry point to this + * code and use it to further limit how far back we search + * when determining if we're in an atomic sequence. If we could + * not find any symbol skip the atomic test altogether as we + * could otherwise end up searching irrelevant text/literals. + * KPROBES depends on KALLSYMS so this last case should never + * happen. + */ + if (kallsyms_lookup_size_offset((unsigned long) addr, &size, &offset)) { + if (offset < (MAX_ATOMIC_CONTEXT_SIZE*sizeof(kprobe_opcode_t))) + scan_end = addr - (offset / sizeof(kprobe_opcode_t)); + else + scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE; } -#endif decoded = arm_probe_decode_insn(insn, asi); - if (decoded == INSN_REJECTED || - is_probed_address_atomic(scan_start, scan_end)) - return INSN_REJECTED; + if (decoded != INSN_REJECTED && scan_end) + if (is_probed_address_atomic(addr - 1, scan_end)) + return INSN_REJECTED; return decoded; } |