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Commit 605bfaee authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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hw-breakpoints: Simplify error handling in breakpoint creation requests 



This simplifies the error handling when we create a breakpoint.
We don't need to check the NULL return value corner case anymore
since we have improved perf_event_create_kernel_counter() to
always return an error code in the failure case.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1259210142-5714-3-git-send-regression-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c6567f64

arch/x86/kernel/ptrace.c

+1 −7
Original line number Original line Diff line number Diff line
@@ -657,10 +657,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) 
					       tsk, true);

					       tsk, true);

		thread->ptrace_bps[i] = NULL;

		thread->ptrace_bps[i] = NULL;





		if (!bp) { /* incorrect bp, or we have a bug in bp API */

		/* Incorrect bp, or we have a bug in bp API */

			rc = -EINVAL;

			break;

		}

		if (IS_ERR(bp)) {

		if (IS_ERR(bp)) {

			rc = PTR_ERR(bp);

			rc = PTR_ERR(bp);

			bp = NULL;

			bp = NULL;
@@ -729,9 +726,6 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr, 
					       tsk,

					       tsk,

					       bp->attr.disabled);

					       bp->attr.disabled);

	}

	}



	if (!bp)

		return -EIO;

	/*

	/*

	 * CHECKME: the previous code returned -EIO if the addr wasn't a

	 * CHECKME: the previous code returned -EIO if the addr wasn't a

	 * valid task virtual addr. The new one will return -EINVAL in this

	 * valid task virtual addr. The new one will return -EINVAL in this

kernel/hw_breakpoint.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -442,7 +442,7 @@ register_wide_hw_breakpoint(unsigned long addr, 




		*pevent = bp;

		*pevent = bp;





		if (IS_ERR(bp) || !bp) {

		if (IS_ERR(bp)) {

			err = PTR_ERR(bp);

			err = PTR_ERR(bp);

			goto fail;

			goto fail;

		}

		}
@@ -453,7 +453,7 @@ register_wide_hw_breakpoint(unsigned long addr, 
fail:

fail:

	for_each_possible_cpu(cpu) {

	for_each_possible_cpu(cpu) {

		pevent = per_cpu_ptr(cpu_events, cpu);

		pevent = per_cpu_ptr(cpu_events, cpu);

		if (IS_ERR(*pevent) || !*pevent)

		if (IS_ERR(*pevent))

			break;

			break;

		unregister_hw_breakpoint(*pevent);

		unregister_hw_breakpoint(*pevent);

	}

	}

kernel/trace/trace_ksym.c

+4 −12
Original line number Original line Diff line number Diff line
@@ -200,12 +200,9 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr) 
	entry->ksym_hbp = register_wide_hw_breakpoint(entry->ksym_addr,

	entry->ksym_hbp = register_wide_hw_breakpoint(entry->ksym_addr,

					entry->len, entry->type,

					entry->len, entry->type,

					ksym_hbp_handler, true);

					ksym_hbp_handler, true);



	if (IS_ERR(entry->ksym_hbp)) {

	if (IS_ERR(entry->ksym_hbp)) {

		entry->ksym_hbp = NULL;

		ret = PTR_ERR(entry->ksym_hbp);

		ret = PTR_ERR(entry->ksym_hbp);

	}



	if (!entry->ksym_hbp) {

		printk(KERN_INFO "ksym_tracer request failed. Try again"

		printk(KERN_INFO "ksym_tracer request failed. Try again"

					" later!!\n");

					" later!!\n");

		goto err;

		goto err;
@@ -332,22 +329,17 @@ static ssize_t ksym_trace_filter_write(struct file *file, 
	if (changed) {

	if (changed) {

		unregister_wide_hw_breakpoint(entry->ksym_hbp);

		unregister_wide_hw_breakpoint(entry->ksym_hbp);

		entry->type = op;

		entry->type = op;

		ret = 0;

		if (op > 0) {

		if (op > 0) {

			entry->ksym_hbp =

			entry->ksym_hbp =

				register_wide_hw_breakpoint(entry->ksym_addr,

				register_wide_hw_breakpoint(entry->ksym_addr,

					entry->len, entry->type,

					entry->len, entry->type,

					ksym_hbp_handler, true);

					ksym_hbp_handler, true);

			if (IS_ERR(entry->ksym_hbp))

			if (IS_ERR(entry->ksym_hbp))

				entry->ksym_hbp = NULL;

				ret = PTR_ERR(entry->ksym_hbp);



			else

			/* modified without problem */

			if (entry->ksym_hbp) {

				ret = 0;

				goto out;

				goto out;

		}

		}

		} else {

			ret = 0;

		}

		/* Error or "symbol:---" case: drop it */

		/* Error or "symbol:---" case: drop it */

		ksym_filter_entry_count--;

		ksym_filter_entry_count--;

		hlist_del_rcu(&(entry->ksym_hlist));

		hlist_del_rcu(&(entry->ksym_hlist));

samples/hw_breakpoint/data_breakpoint.c

+0 −3
Original line number Original line Diff line number Diff line
@@ -61,9 +61,6 @@ static int __init hw_break_module_init(void) 
	if (IS_ERR(sample_hbp)) {

	if (IS_ERR(sample_hbp)) {

		ret = PTR_ERR(sample_hbp);

		ret = PTR_ERR(sample_hbp);

		goto fail;

		goto fail;

	} else if (!sample_hbp) {

		ret = -EINVAL;

		goto fail;

	}

	}





	printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);

	printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);