Commit 49dc6fbc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'kgdb-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux 

Pull kgdb updates from Daniel Thompson:
 "A fairly modest set of changes for this cycle.

  Of particular note are an earlycon fix from Doug Anderson and my own
  changes to get kgdb/kdb to honour the kprobe blocklist. The later
  creates a safety rail that strongly encourages developers not to place
  breakpoints in, for example, arch specific trap handling code.

  Also included are a couple of small fixes and tweaks: an API update,
  eliminate a coverity dead code warning, improved handling of search
  during multi-line printk and a couple of typo corrections"

* tag 'kgdb-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kdb: Fix pager search for multi-line strings
  kernel: debug: Centralize dbg_[de]activate_sw_breakpoints
  kgdb: Add NOKPROBE labels on the trap handler functions
  kgdb: Honour the kprobe blocklist when setting breakpoints
  kernel/debug: Fix spelling mistake in debug_core.c
  kdb: Use newer api for tasklist scanning
  kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"
  kdb: remove unnecessary null check of dbg_io_ops
parents 09a31a7e d081a6e3

include/linux/kgdb.h

+18 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/linkage.h>

#include <linux/init.h>

#include <linux/atomic.h>

#include <linux/kprobes.h>

#ifdef CONFIG_HAVE_ARCH_KGDB

#include <asm/kgdb.h>

#endif
@@ -335,6 +336,23 @@ extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, 
			  atomic_t *snd_rdy);

extern void gdbstub_exit(int status);



/*

 * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense

 * given they are both typically hooked up to the same trap meaning on most

 * architectures one cannot be used to debug the other)

 *

 * However on architectures where kprobes is not (yet) implemented we permit

 * breakpoints everywhere rather than blocking everything by default.

 */

static inline bool kgdb_within_blocklist(unsigned long addr)

{

#ifdef CONFIG_KGDB_HONOUR_BLOCKLIST

	return within_kprobe_blacklist(addr);

#else

	return false;

#endif

}



extern int			kgdb_single_step;

extern atomic_t			kgdb_active;

#define in_dbg_master() \

kernel/debug/debug_core.c

+38 −10
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ static int exception_level; 
struct kgdb_io		*dbg_io_ops;

static DEFINE_SPINLOCK(kgdb_registration_lock);



/* Action for the reboot notifiter, a global allow kdb to change it */

/* Action for the reboot notifier, a global allow kdb to change it */

static int kgdbreboot;

/* kgdb console driver is loaded */

static int kgdb_con_registered;
@@ -94,14 +94,6 @@ int dbg_switch_cpu; 
/* Use kdb or gdbserver mode */

int dbg_kdb_mode = 1;



static int __init opt_kgdb_con(char *str)

{

	kgdb_use_con = 1;

	return 0;

}



early_param("kgdbcon", opt_kgdb_con);



module_param(kgdb_use_con, int, 0644);

module_param(kgdbreboot, int, 0644);
@@ -163,7 +155,7 @@ early_param("nokgdbroundup", opt_nokgdbroundup); 


/*

 * Weak aliases for breakpoint management,

 * can be overriden by architectures when needed:

 * can be overridden by architectures when needed:

 */

int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)

{
@@ -177,17 +169,23 @@ int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 
				 arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);

	return err;

}

NOKPROBE_SYMBOL(kgdb_arch_set_breakpoint);



int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)

{

	return copy_to_kernel_nofault((char *)bpt->bpt_addr,

				  (char *)bpt->saved_instr, BREAK_INSTR_SIZE);

}

NOKPROBE_SYMBOL(kgdb_arch_remove_breakpoint);



int __weak kgdb_validate_break_address(unsigned long addr)

{

	struct kgdb_bkpt tmp;

	int err;



	if (kgdb_within_blocklist(addr))

		return -EINVAL;



	/* Validate setting the breakpoint and then removing it.  If the

	 * remove fails, the kernel needs to emit a bad message because we

	 * are deep trouble not being able to put things back the way we
@@ -208,6 +206,7 @@ unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) 
{

	return instruction_pointer(regs);

}

NOKPROBE_SYMBOL(kgdb_arch_pc);



int __weak kgdb_arch_init(void)

{
@@ -218,6 +217,7 @@ int __weak kgdb_skipexception(int exception, struct pt_regs *regs) 
{

	return 0;

}

NOKPROBE_SYMBOL(kgdb_skipexception);



#ifdef CONFIG_SMP
@@ -239,6 +239,7 @@ void __weak kgdb_call_nmi_hook(void *ignored) 
	 */

	kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());

}

NOKPROBE_SYMBOL(kgdb_call_nmi_hook);



void __weak kgdb_roundup_cpus(void)

{
@@ -272,6 +273,7 @@ void __weak kgdb_roundup_cpus(void) 
			kgdb_info[cpu].rounding_up = false;

	}

}

NOKPROBE_SYMBOL(kgdb_roundup_cpus);



#endif
@@ -298,6 +300,7 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) 
	/* Force flush instruction cache if it was outside the mm */

	flush_icache_range(addr, addr + BREAK_INSTR_SIZE);

}

NOKPROBE_SYMBOL(kgdb_flush_swbreak_addr);



/*

 * SW breakpoint management:
@@ -325,6 +328,7 @@ int dbg_activate_sw_breakpoints(void) 
	}

	return ret;

}

NOKPROBE_SYMBOL(dbg_activate_sw_breakpoints);



int dbg_set_sw_break(unsigned long addr)

{
@@ -388,6 +392,7 @@ int dbg_deactivate_sw_breakpoints(void) 
	}

	return ret;

}

NOKPROBE_SYMBOL(dbg_deactivate_sw_breakpoints);



int dbg_remove_sw_break(unsigned long addr)

{
@@ -509,6 +514,7 @@ static int kgdb_io_ready(int print_wait) 
	}

	return 1;

}

NOKPROBE_SYMBOL(kgdb_io_ready);



static int kgdb_reenter_check(struct kgdb_state *ks)

{
@@ -556,6 +562,7 @@ static int kgdb_reenter_check(struct kgdb_state *ks) 


	return 1;

}

NOKPROBE_SYMBOL(kgdb_reenter_check);



static void dbg_touch_watchdogs(void)

{
@@ -563,6 +570,7 @@ static void dbg_touch_watchdogs(void) 
	clocksource_touch_watchdog();

	rcu_cpu_stall_reset();

}

NOKPROBE_SYMBOL(dbg_touch_watchdogs);



static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,

		int exception_state)
@@ -752,6 +760,8 @@ cpu_master_loop: 
		}

	}



	dbg_activate_sw_breakpoints();



	/* Call the I/O driver's post_exception routine */

	if (dbg_io_ops->post_exception)

		dbg_io_ops->post_exception();
@@ -794,6 +804,7 @@ kgdb_restore: 


	return kgdb_info[cpu].ret_state;

}

NOKPROBE_SYMBOL(kgdb_cpu_enter);



/*

 * kgdb_handle_exception() - main entry point from a kernel exception
@@ -838,6 +849,7 @@ out: 
		arch_kgdb_ops.enable_nmi(1);

	return ret;

}

NOKPROBE_SYMBOL(kgdb_handle_exception);



/*

 * GDB places a breakpoint at this function to know dynamically loaded objects.
@@ -872,6 +884,7 @@ int kgdb_nmicallback(int cpu, void *regs) 
#endif

	return 1;

}

NOKPROBE_SYMBOL(kgdb_nmicallback);



int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,

							atomic_t *send_ready)
@@ -897,6 +910,7 @@ int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, 
#endif

	return 1;

}

NOKPROBE_SYMBOL(kgdb_nmicallin);



static void kgdb_console_write(struct console *co, const char *s,

   unsigned count)
@@ -920,6 +934,20 @@ static struct console kgdbcons = { 
	.index		= -1,

};



static int __init opt_kgdb_con(char *str)

{

	kgdb_use_con = 1;



	if (kgdb_io_module_registered && !kgdb_con_registered) {

		register_console(&kgdbcons);

		kgdb_con_registered = 1;

	}



	return 0;

}



early_param("kgdbcon", opt_kgdb_con);



#ifdef CONFIG_MAGIC_SYSRQ

static void sysrq_handle_dbg(int key)

{

kernel/debug/gdbstub.c

+2 −3
Original line number Diff line number Diff line
@@ -725,7 +725,7 @@ static void gdb_cmd_query(struct kgdb_state *ks) 
			}

		}



		do_each_thread(g, p) {

		for_each_process_thread(g, p) {

			if (i >= ks->thr_query && !finished) {

				int_to_threadref(thref, p->pid);

				ptr = pack_threadid(ptr, thref);
@@ -735,7 +735,7 @@ static void gdb_cmd_query(struct kgdb_state *ks) 
					finished = 1;

			}

			i++;

		} while_each_thread(g, p);

		}



		*(--ptr) = '\0';

		break;
@@ -1061,7 +1061,6 @@ int gdb_serial_stub(struct kgdb_state *ks) 
				error_packet(remcom_out_buffer, -EINVAL);

				break;

			}

			dbg_activate_sw_breakpoints();

			fallthrough;	/* to default processing */

		default:

default_handle:

kernel/debug/kdb/kdb_bp.c

+9 −0
Original line number Diff line number Diff line
@@ -306,6 +306,15 @@ static int kdb_bp(int argc, const char **argv) 
	if (!template.bp_addr)

		return KDB_BADINT;



	/*

	 * This check is redundant (since the breakpoint machinery should

	 * be doing the same check during kdb_bp_install) but gives the

	 * user immediate feedback.

	 */

	diag = kgdb_validate_break_address(template.bp_addr);

	if (diag)

		return diag;



	/*

	 * Find an empty bp structure to allocate

	 */

kernel/debug/kdb/kdb_bt.c

+2 −2
Original line number Diff line number Diff line
@@ -149,14 +149,14 @@ kdb_bt(int argc, const char **argv) 
				return 0;

		}

		/* Now the inactive tasks */

		kdb_do_each_thread(g, p) {

		for_each_process_thread(g, p) {

			if (KDB_FLAG(CMD_INTERRUPT))

				return 0;

			if (task_curr(p))

				continue;

			if (kdb_bt1(p, mask, btaprompt))

				return 0;

		} kdb_while_each_thread(g, p);

		}

	} else if (strcmp(argv[0], "btp") == 0) {

		struct task_struct *p;

		unsigned long pid;

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