diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 20a5b368946..dd74fe7273b 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -86,9 +86,15 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) gdb_regs[GDB_DS] = regs->ds; gdb_regs[GDB_ES] = regs->es; gdb_regs[GDB_CS] = regs->cs; - gdb_regs[GDB_SS] = __KERNEL_DS; gdb_regs[GDB_FS] = 0xFFFF; gdb_regs[GDB_GS] = 0xFFFF; + if (user_mode_vm(regs)) { + gdb_regs[GDB_SS] = regs->ss; + gdb_regs[GDB_SP] = regs->sp; + } else { + gdb_regs[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_SP] = kernel_stack_pointer(regs); + } #else gdb_regs[GDB_R8] = regs->r8; gdb_regs[GDB_R9] = regs->r9; @@ -101,8 +107,8 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) gdb_regs32[GDB_PS] = regs->flags; gdb_regs32[GDB_CS] = regs->cs; gdb_regs32[GDB_SS] = regs->ss; -#endif gdb_regs[GDB_SP] = kernel_stack_pointer(regs); +#endif } /** @@ -220,8 +226,7 @@ static void kgdb_correct_hw_break(void) dr7 |= ((breakinfo[breakno].len << 2) | breakinfo[breakno].type) << ((breakno << 2) + 16); - if (breakno >= 0 && breakno <= 3) - set_debugreg(breakinfo[breakno].addr, breakno); + set_debugreg(breakinfo[breakno].addr, breakno); } else { if ((dr7 & breakbit) && !breakinfo[breakno].enabled) { @@ -395,7 +400,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, /* set the trace bit if we're stepping */ if (remcomInBuffer[0] == 's') { linux_regs->flags |= X86_EFLAGS_TF; - kgdb_single_step = 1; atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id()); } diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index e4ff50b95a5..fcb6ec1af17 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -712,6 +712,12 @@ static int run_simple_test(int is_get_char, int chr) /* End of packet == #XX so look for the '#' */ if (put_buf_cnt > 3 && put_buf[put_buf_cnt - 3] == '#') { + if (put_buf_cnt >= BUFMAX) { + eprintk("kgdbts: ERROR: put buffer overflow on" + " '%s' line %i\n", ts.name, ts.idx); + put_buf_cnt = 0; + return 0; + } put_buf[put_buf_cnt] = '\0'; v2printk("put%i: %s\n", ts.idx, put_buf); /* Trigger check here */ @@ -885,16 +891,16 @@ static void kgdbts_run_tests(void) int nmi_sleep = 0; int i; - ptr = strstr(config, "F"); + ptr = strchr(config, 'F'); if (ptr) fork_test = simple_strtol(ptr + 1, NULL, 10); - ptr = strstr(config, "S"); + ptr = strchr(config, 'S'); if (ptr) do_sys_open_test = simple_strtol(ptr + 1, NULL, 10); - ptr = strstr(config, "N"); + ptr = strchr(config, 'N'); if (ptr) nmi_sleep = simple_strtol(ptr+1, NULL, 10); - ptr = strstr(config, "I"); + ptr = strchr(config, 'I'); if (ptr) sstep_test = simple_strtol(ptr+1, NULL, 10); diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 7d701463402..2eb517e2351 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -129,6 +129,7 @@ struct task_struct *kgdb_usethread; struct task_struct *kgdb_contthread; int kgdb_single_step; +pid_t kgdb_sstep_pid; /* Our I/O buffers. */ static char remcom_in_buffer[BUFMAX]; @@ -541,12 +542,17 @@ static struct task_struct *getthread(struct pt_regs *regs, int tid) */ if (tid == 0 || tid == -1) tid = -atomic_read(&kgdb_active) - 2; - if (tid < 0) { + if (tid < -1 && tid > -NR_CPUS - 2) { if (kgdb_info[-tid - 2].task) return kgdb_info[-tid - 2].task; else return idle_task(-tid - 2); } + if (tid <= 0) { + printk(KERN_ERR "KGDB: Internal thread select error\n"); + dump_stack(); + return NULL; + } /* * find_task_by_pid_ns() does not take the tasklist lock anymore @@ -619,7 +625,8 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) static int kgdb_activate_sw_breakpoints(void) { unsigned long addr; - int error = 0; + int error; + int ret = 0; int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { @@ -629,13 +636,16 @@ static int kgdb_activate_sw_breakpoints(void) addr = kgdb_break[i].bpt_addr; error = kgdb_arch_set_breakpoint(addr, kgdb_break[i].saved_instr); - if (error) - return error; + if (error) { + ret = error; + printk(KERN_INFO "KGDB: BP install failed: %lx", addr); + continue; + } kgdb_flush_swbreak_addr(addr); kgdb_break[i].state = BP_ACTIVE; } - return 0; + return ret; } static int kgdb_set_sw_break(unsigned long addr) @@ -682,7 +692,8 @@ static int kgdb_set_sw_break(unsigned long addr) static int kgdb_deactivate_sw_breakpoints(void) { unsigned long addr; - int error = 0; + int error; + int ret = 0; int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { @@ -691,13 +702,15 @@ static int kgdb_deactivate_sw_breakpoints(void) addr = kgdb_break[i].bpt_addr; error = kgdb_arch_remove_breakpoint(addr, kgdb_break[i].saved_instr); - if (error) - return error; + if (error) { + printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr); + ret = error; + } kgdb_flush_swbreak_addr(addr); kgdb_break[i].state = BP_SET; } - return 0; + return ret; } static int kgdb_remove_sw_break(unsigned long addr) @@ -1204,8 +1217,10 @@ static int gdb_cmd_exception_pass(struct kgdb_state *ks) return 1; } else { - error_packet(remcom_out_buffer, -EINVAL); - return 0; + kgdb_msg_write("KGDB only knows signal 9 (pass)" + " and 15 (pass and disconnect)\n" + "Executing a continue without signal passing\n", 0); + remcom_in_buffer[0] = 'c'; } /* Indicate fall through */ @@ -1395,6 +1410,7 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) struct kgdb_state kgdb_var; struct kgdb_state *ks = &kgdb_var; unsigned long flags; + int sstep_tries = 100; int error = 0; int i, cpu; @@ -1425,13 +1441,14 @@ acquirelock: cpu_relax(); /* - * Do not start the debugger connection on this CPU if the last - * instance of the exception handler wanted to come into the - * debugger on a different CPU via a single step + * For single stepping, try to only enter on the processor + * that was single stepping. To gaurd against a deadlock, the + * kernel will only try for the value of sstep_tries before + * giving up and continuing on. */ if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && - atomic_read(&kgdb_cpu_doing_single_step) != cpu) { - + (kgdb_info[cpu].task && + kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { atomic_set(&kgdb_active, -1); touch_softlockup_watchdog(); clocksource_touch_watchdog(); @@ -1524,6 +1541,13 @@ acquirelock: } kgdb_restore: + if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { + int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); + if (kgdb_info[sstep_cpu].task) + kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; + else + kgdb_sstep_pid = 0; + } /* Free kgdb_active */ atomic_set(&kgdb_active, -1); touch_softlockup_watchdog();