From e5dd03c411713c066b94e1d448359e5216115c1c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:06 +0200 Subject: [PATCH] tracing: Change tracing_entries_fops to rely on tracing_get_cpu() commit 0bc392ee46d0fd8e6b678457ef71f074f19a03c5 upstream. tracing_open_generic_tc() is racy, the memory inode->i_private points to can be already freed. 1. Change its last user, tracing_entries_fops, to use tracing_*_generic_tr() instead. 2. Change debugfs_create_file("buffer_size_kb", data) callers to pass "data = tr". 3. Change tracing_entries_read() and tracing_entries_write() to use tracing_get_cpu(). 4. Kill the no longer used tracing_open_generic_tc() and tracing_release_generic_tc(). Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 49 ++++++++++++------------------------------------- 1 file changed, 12 insertions(+), 37 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 801d72b..83fba3c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2975,23 +2975,6 @@ int tracing_open_generic_tr(struct inode *inode, struct file *filp) return 0; } -int tracing_open_generic_tc(struct inode *inode, struct file *filp) -{ - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; - - if (tracing_disabled) - return -ENODEV; - - if (trace_array_get(tr) < 0) - return -ENODEV; - - filp->private_data = inode->i_private; - - return 0; - -} - static int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; @@ -3045,15 +3028,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file) return 0; } -static int tracing_release_generic_tc(struct inode *inode, struct file *file) -{ - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; - - trace_array_put(tr); - return 0; -} - static int tracing_single_release_tr(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; @@ -4374,15 +4348,16 @@ static ssize_t tracing_entries_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_cpu *tc = filp->private_data; - struct trace_array *tr = tc->tr; + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; + int cpu = tracing_get_cpu(inode); char buf[64]; int r = 0; ssize_t ret; mutex_lock(&trace_types_lock); - if (tc->cpu == RING_BUFFER_ALL_CPUS) { + if (cpu == RING_BUFFER_ALL_CPUS) { int cpu, buf_size_same; unsigned long size; @@ -4409,7 +4384,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf, } else r = sprintf(buf, "X\n"); } else - r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10); + r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10); mutex_unlock(&trace_types_lock); @@ -4421,7 +4396,8 @@ static ssize_t tracing_entries_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_cpu *tc = filp->private_data; + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; unsigned long val; int ret; @@ -4435,8 +4411,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, /* value is in KB */ val <<= 10; - - ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu); + ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode)); if (ret < 0) return ret; @@ -4884,11 +4859,11 @@ static const struct file_operations tracing_pipe_fops = { }; static const struct file_operations tracing_entries_fops = { - .open = tracing_open_generic_tc, + .open = tracing_open_generic_tr, .read = tracing_entries_read, .write = tracing_entries_write, .llseek = generic_file_llseek, - .release = tracing_release_generic_tc, + .release = tracing_release_generic_tr, }; static const struct file_operations tracing_total_entries_fops = { @@ -5572,7 +5547,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) tr, cpu, &tracing_stats_fops); trace_create_cpu_file("buffer_size_kb", 0444, d_cpu, - &data->trace_cpu, cpu, &tracing_entries_fops); + tr, cpu, &tracing_entries_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_cpu_file("snapshot", 0644, d_cpu, @@ -6148,7 +6123,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) tr, &tracing_pipe_fops); trace_create_file("buffer_size_kb", 0644, d_tracer, - (void *)&tr->trace_cpu, &tracing_entries_fops); + tr, &tracing_entries_fops); trace_create_file("buffer_total_size_kb", 0444, d_tracer, tr, &tracing_total_entries_fops); -- 2.7.4