From 0f17976568b3f72e676450af0c0db6f8752253d6 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 29 Jun 2017 10:05:45 -0400 Subject: [PATCH 1/2] ftrace: Fix regression with module command in stack_trace_filter When doing the following command: # echo ":mod:kvm_intel" > /sys/kernel/tracing/stack_trace_filter it triggered a crash. This happened with the clean up of probes. It required all callers to the regex function (doing ftrace filtering) to have ops->private be a pointer to a trace_array. But for the stack tracer, that is not the case. Allow for the ops->private to be NULL, and change the function command callbacks to handle the trace_array pointer being NULL as well. Fixes: d2afd57a4b96 ("tracing/ftrace: Allow instances to have their own function probes") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 3 --- kernel/trace/trace.c | 3 +++ kernel/trace/trace_functions.c | 12 ++++++++++++ kernel/trace/trace_stack.c | 6 ++++-- 4 files changed, 19 insertions(+), 5 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9e5841dc14b5..b308be30dfb9 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4337,9 +4337,6 @@ static int ftrace_process_regex(struct ftrace_iterator *iter, command = strsep(&next, ":"); - if (WARN_ON_ONCE(!tr)) - return -EINVAL; - mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(p->name, command) == 0) { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1122f151466f..091e801145c9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6881,6 +6881,9 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, char *number; int ret; + if (!tr) + return -ENODEV; + /* hash funcs only work with set_ftrace_filter */ if (!enable) return -EINVAL; diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index a3bddbfd0874..a0910c0cdf2e 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -654,6 +654,9 @@ ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash, { struct ftrace_probe_ops *ops; + if (!tr) + return -ENODEV; + /* we register both traceon and traceoff to this callback */ if (strcmp(cmd, "traceon") == 0) ops = param ? &traceon_count_probe_ops : &traceon_probe_ops; @@ -670,6 +673,9 @@ ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash, { struct ftrace_probe_ops *ops; + if (!tr) + return -ENODEV; + ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops; return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd, @@ -682,6 +688,9 @@ ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash, { struct ftrace_probe_ops *ops; + if (!tr) + return -ENODEV; + ops = &dump_probe_ops; /* Only dump once. */ @@ -695,6 +704,9 @@ ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash, { struct ftrace_probe_ops *ops; + if (!tr) + return -ENODEV; + ops = &cpudump_probe_ops; /* Only dump once. */ diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 76aa04d4c925..b4a751e8f9d6 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -409,7 +409,9 @@ static const struct file_operations stack_trace_fops = { static int stack_trace_filter_open(struct inode *inode, struct file *file) { - return ftrace_regex_open(&trace_ops, FTRACE_ITER_FILTER, + struct ftrace_ops *ops = inode->i_private; + + return ftrace_regex_open(ops, FTRACE_ITER_FILTER, inode, file); } @@ -476,7 +478,7 @@ static __init int stack_trace_init(void) NULL, &stack_trace_fops); trace_create_file("stack_trace_filter", 0444, d_tracer, - NULL, &stack_trace_filter_fops); + &trace_ops, &stack_trace_filter_fops); if (stack_trace_filter_buf[0]) ftrace_set_early_filter(&trace_ops, stack_trace_filter_buf, 1); From 9e52b32567126fe146f198971364f68d3bc5233f Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Thu, 22 Jun 2017 11:24:42 +0200 Subject: [PATCH 2/2] tracing/kprobes: Allow to create probe with a module name starting with a digit Always try to parse an address, since kstrtoul() will safely fail when given a symbol as input. If that fails (which will be the case for a symbol), try to parse a symbol instead. This allows creating a probe such as: p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0 Which is necessary for this command to work: perf probe -m 8021q -a vlan_gro_receive Link: http://lkml.kernel.org/r/fd72d666f45b114e2c5b9cf7e27b91de1ec966f1.1498122881.git.sd@queasysnail.net Cc: stable@vger.kernel.org Fixes: 413d37d1e ("tracing: Add kprobe-based event tracer") Acked-by: Masami Hiramatsu Signed-off-by: Sabrina Dubroca Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_kprobe.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index c129fca6ec99..b53c8d369163 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -707,20 +707,16 @@ static int create_trace_kprobe(int argc, char **argv) pr_info("Probe point is not specified.\n"); return -EINVAL; } - if (isdigit(argv[1][0])) { - /* an address specified */ - ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr); - if (ret) { - pr_info("Failed to parse address.\n"); - return ret; - } - } else { + + /* try to parse an address. if that fails, try to read the + * input as a symbol. */ + if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { /* a symbol specified */ symbol = argv[1]; /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); if (ret) { - pr_info("Failed to parse symbol.\n"); + pr_info("Failed to parse either an address or a symbol.\n"); return ret; } if (offset && is_return &&