Merge tag 'probes-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull kprobes updates from Masami Hiramatsu:

 - Skip negative return code check for snprintf in eprobe

 - Add recursive call test cases for kprobe unit test

 - Add 'char' type to probe events to show it as the character instead
   of value

 - Update kselftest kprobe-event testcase to ignore '__pfx_' symbols

 - Fix kselftest to check filter on eprobe event correctly

 - Add filter on eprobe to the README file in tracefs

 - Fix optprobes to check whether there is 'under unoptimizing' optprobe
   when optimizing another kprobe correctly

 - Fix optprobe to check whether there is 'under unoptimizing' optprobe
   when fetching the original instruction correctly

 - Fix optprobe to free 'forcibly unoptimized' optprobe correctly

* tag 'probes-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/eprobe: no need to check for negative ret value for snprintf
  test_kprobes: Add recursed kprobe test case
  tracing/probe: add a char type to show the character value of traced arguments
  selftests/ftrace: Fix probepoint testcase to ignore __pfx_* symbols
  selftests/ftrace: Fix eprobe syntax test case to check filter support
  tracing/eprobe: Fix to add filter on eprobe description in README file
  x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe range
  x86/kprobes: Fix __recover_optprobed_insn check optimizing logic
  kprobes: Fix to handle forcibly unoptimized kprobes on freeing_list

5 files changed, 21 insertions, 25 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1c18ecf9f98b..00e177de91cc 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -458,7 +458,7 @@ static inline int kprobe_optready(struct kprobe *p)
 }
 
 /* Return true if the kprobe is disarmed. Note: p must be on hash list */
-static inline bool kprobe_disarmed(struct kprobe *p)
+bool kprobe_disarmed(struct kprobe *p)
 {
 	struct optimized_kprobe *op;
 
@@ -555,17 +555,15 @@ static void do_unoptimize_kprobes(void)
 	/* See comment in do_optimize_kprobes() */
 	lockdep_assert_cpus_held();
 
-	/* Unoptimization must be done anytime */
-	if (list_empty(&unoptimizing_list))
-		return;
+	if (!list_empty(&unoptimizing_list))
+		arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
 
-	arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
-	/* Loop on 'freeing_list' for disarming */
+	/* Loop on 'freeing_list' for disarming and removing from kprobe hash list */
 	list_for_each_entry_safe(op, tmp, &freeing_list, list) {
 		/* Switching from detour code to origin */
 		op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
-		/* Disarm probes if marked disabled */
-		if (kprobe_disabled(&op->kp))
+		/* Disarm probes if marked disabled and not gone */
+		if (kprobe_disabled(&op->kp) && !kprobe_gone(&op->kp))
 			arch_disarm_kprobe(&op->kp);
 		if (kprobe_unused(&op->kp)) {
 			/*
@@ -662,7 +660,7 @@ void wait_for_kprobe_optimizer(void)
 	mutex_unlock(&kprobe_mutex);
 }
 
-static bool optprobe_queued_unopt(struct optimized_kprobe *op)
+bool optprobe_queued_unopt(struct optimized_kprobe *op)
 {
 	struct optimized_kprobe *_op;
 
@@ -797,14 +795,13 @@ static void kill_optimized_kprobe(struct kprobe *p)
 	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
 
 	if (kprobe_unused(p)) {
-		/* Enqueue if it is unused */
-		list_add(&op->list, &freeing_list);
 		/*
-		 * Remove unused probes from the hash list. After waiting
-		 * for synchronization, this probe is reclaimed.
-		 * (reclaiming is done by do_free_cleaned_kprobes().)
+		 * Unused kprobe is on unoptimizing or freeing list. We move it
+		 * to freeing_list and let the kprobe_optimizer() remove it from
+		 * the kprobe hash list and free it.
 		 */
-		hlist_del_rcu(&op->kp.hlist);
+		if (optprobe_queued_unopt(op))
+			list_move(&op->list, &freeing_list);
 	}
 
 	/* Don't touch the code, because it is already freed. */
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0fa59acfea17..45551c7b4c36 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5646,7 +5646,7 @@ static const char readme_msg[] =
 #ifdef CONFIG_HIST_TRIGGERS
 	"\t           s:[synthetic/]<event> <field> [<field>]\n"
 #endif
-	"\t           e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>]\n"
+	"\t           e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
 	"\t           -:[<group>/][<event>]\n"
 #ifdef CONFIG_KPROBE_EVENTS
 	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
@@ -5663,7 +5663,7 @@ static const char readme_msg[] =
 	"\t           $stack<index>, $stack, $retval, $comm,\n"
 #endif
 	"\t           +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
-	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
+	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
 	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
 	"\t           symstr, <type>\\[<array-size>\\]\n"
 #ifdef CONFIG_HIST_TRIGGERS
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 352b65e2b910..594ac1d086aa 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -923,17 +923,13 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch
 
 	p = ep->filter_str;
 	for (i = 0; i < argc; i++) {
-		ret = snprintf(p, len, "%s ", argv[i]);
-		if (ret < 0)
-			goto error;
-		if (ret > len) {
-			ret = -E2BIG;
-			goto error;
-		}
+		if (i)
+			ret = snprintf(p, len, " %s", argv[i]);
+		else
+			ret = snprintf(p, len, "%s", argv[i]);
 		p += ret;
 		len -= ret;
 	}
-	p[-1] = '\0';
 
 	/*
 	 * Ensure the filter string can be parsed correctly. Note, this
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 01ebabbbe8c9..11008c098727 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -50,6 +50,7 @@ DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
+DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
 
 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
 {
@@ -95,6 +96,7 @@ static const struct fetch_type probe_fetch_types[] = {
 	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
+	ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8,  0),
 	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
 
 	ASSIGN_FETCH_TYPE_END
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 23acfd1c3812..b4f99553411e 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -166,6 +166,7 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
 DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
 DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
 
+DECLARE_BASIC_PRINT_TYPE_FUNC(char);
 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 DECLARE_BASIC_PRINT_TYPE_FUNC(symbol);