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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-20 21:19:48 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-20 21:19:48 +0300
commit45979a956b92c9bab652a2c4a5c39d8f94f6df2c (patch)
treeb13d28f9069a6acd9b02277063871fbeec5e5a95 /kernel/kprobes.c
parent3207598ab00e0fb06c8d73c9ae567afa4847e70e (diff)
parentb78b94b82122208902c0f83805e614e1239f9893 (diff)
downloadlinux-45979a956b92c9bab652a2c4a5c39d8f94f6df2c.tar.xz
Merge tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt: - Addition of multiprobes to kprobe and uprobe events (allows for more than one probe attached to the same location) - Addition of adding immediates to probe parameters - Clean up of the recordmcount.c code. This brings us closer to merging recordmcount into objtool, and reuse code. - Other small clean ups * tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits) selftests/ftrace: Update kprobe event error testcase tracing/probe: Reject exactly same probe event tracing/probe: Fix to allow user to enable events on unloaded modules selftests/ftrace: Select an existing function in kprobe_eventname test tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink() tracing: Make sure variable reference alias has correct var_ref_idx tracing: Be more clever when dumping hex in __print_hex() ftrace: Simplify ftrace hash lookup code in clear_func_from_hash() tracing: Add "gfp_t" support in synthetic_events tracing: Rename tracing_reset() to tracing_reset_cpu() tracing: Document the stack trace algorithm in the comments tracing/arm64: Have max stack tracer handle the case of return address after data recordmcount: Clarify what cleanup() does recordmcount: Remove redundant cleanup() calls recordmcount: Kernel style formatting recordmcount: Kernel style function signature formatting recordmcount: Rewrite error/success handling selftests/ftrace: Add syntax error test for multiprobe selftests/ftrace: Add syntax error test for immediates selftests/ftrace: Add a testcase for kprobe multiprobe event ...
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c56
1 files changed, 40 insertions, 16 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1b66ccbb744a..53534aa258a6 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -962,8 +962,15 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
.func = kprobe_ftrace_handler,
+ .flags = FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
+ .func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
};
+
+static int kprobe_ipmodify_enabled;
static int kprobe_ftrace_enabled;
/* Must ensure p->addr is really on ftrace */
@@ -976,58 +983,75 @@ static int prepare_kprobe(struct kprobe *p)
}
/* Caller must lock kprobe_mutex */
-static int arm_kprobe_ftrace(struct kprobe *p)
+static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
{
int ret = 0;
- ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
- (unsigned long)p->addr, 0, 0);
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
if (ret) {
pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
- if (kprobe_ftrace_enabled == 0) {
- ret = register_ftrace_function(&kprobe_ftrace_ops);
+ if (*cnt == 0) {
+ ret = register_ftrace_function(ops);
if (ret) {
pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
goto err_ftrace;
}
}
- kprobe_ftrace_enabled++;
+ (*cnt)++;
return ret;
err_ftrace:
/*
- * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
- * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
- * empty filter_hash which would undesirably trace all functions.
+ * At this point, sinec ops is not registered, we should be sefe from
+ * registering empty filter.
*/
- ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
+ ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
return ret;
}
+static int arm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __arm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+
/* Caller must lock kprobe_mutex */
-static int disarm_kprobe_ftrace(struct kprobe *p)
+static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
{
int ret = 0;
- if (kprobe_ftrace_enabled == 1) {
- ret = unregister_ftrace_function(&kprobe_ftrace_ops);
+ if (*cnt == 1) {
+ ret = unregister_ftrace_function(ops);
if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
return ret;
}
- kprobe_ftrace_enabled--;
+ (*cnt)--;
- ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
- (unsigned long)p->addr, 1, 0);
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
+
+static int disarm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __disarm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
#else /* !CONFIG_KPROBES_ON_FTRACE */
#define prepare_kprobe(p) arch_prepare_kprobe(p)
#define arm_kprobe_ftrace(p) (-ENODEV)