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author | Oleg Nesterov <oleg@redhat.com> | 2013-07-23 15:26:10 (GMT) |
---|---|---|
committer | Steven Rostedt <rostedt@rostedt.homelinux.com> | 2013-07-24 15:22:53 (GMT) |
commit | 6484c71cbc170634fa131b6d022d86d61686b88b (patch) | |
tree | 68f696f4985f368a2fa7f93a2d474fea2c7585db /kernel/trace/trace.c | |
parent | 0bc392ee46d0fd8e6b678457ef71f074f19a03c5 (diff) | |
download | linux-fsl-qoriq-6484c71cbc170634fa131b6d022d86d61686b88b.tar.xz |
tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu()
tracing_open() and tracing_snapshot_open() are racy, the memory
inode->i_private points to can be already freed.
Convert these last users of "inode->i_private == trace_cpu" to
use "i_private = trace_array" and rely on tracing_get_cpu().
v2: incorporate the fix from Steven, tracing_release() must not
blindly dereference file->private_data unless we know that
the file was opened for reading.
Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 50 |
1 files changed, 22 insertions, 28 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 68b4685..dd7780d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2862,9 +2862,9 @@ static const struct seq_operations tracer_seq_ops = { }; static struct trace_iterator * -__tracing_open(struct trace_array *tr, struct trace_cpu *tc, - struct inode *inode, struct file *file, bool snapshot) +__tracing_open(struct inode *inode, struct file *file, bool snapshot) { + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; int cpu; @@ -2905,8 +2905,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc, iter->trace_buffer = &tr->trace_buffer; iter->snapshot = snapshot; iter->pos = -1; + iter->cpu_file = tracing_get_cpu(inode); mutex_init(&iter->mutex); - iter->cpu_file = tc->cpu; /* Notify the tracer early; before we stop tracing. */ if (iter->trace && iter->trace->open) @@ -2986,22 +2986,18 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp) static int tracing_release(struct inode *inode, struct file *file) { + struct trace_array *tr = inode->i_private; struct seq_file *m = file->private_data; struct trace_iterator *iter; - struct trace_array *tr; int cpu; - /* Writes do not use seq_file, need to grab tr from inode */ if (!(file->f_mode & FMODE_READ)) { - struct trace_cpu *tc = inode->i_private; - - trace_array_put(tc->tr); + trace_array_put(tr); return 0; } + /* Writes do not use seq_file */ iter = m->private; - tr = iter->tr; - mutex_lock(&trace_types_lock); for_each_tracing_cpu(cpu) { @@ -3048,8 +3044,7 @@ static int tracing_single_release_tr(struct inode *inode, struct file *file) static int tracing_open(struct inode *inode, struct file *file) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; int ret = 0; @@ -3057,16 +3052,17 @@ static int tracing_open(struct inode *inode, struct file *file) return -ENODEV; /* If this file was open for write, then erase contents */ - if ((file->f_mode & FMODE_WRITE) && - (file->f_flags & O_TRUNC)) { - if (tc->cpu == RING_BUFFER_ALL_CPUS) + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + int cpu = tracing_get_cpu(inode); + + if (cpu == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->trace_buffer); else - tracing_reset(&tr->trace_buffer, tc->cpu); + tracing_reset(&tr->trace_buffer, cpu); } if (file->f_mode & FMODE_READ) { - iter = __tracing_open(tr, tc, inode, file, false); + iter = __tracing_open(inode, file, false); if (IS_ERR(iter)) ret = PTR_ERR(iter); else if (trace_flags & TRACE_ITER_LATENCY_FMT) @@ -4680,8 +4676,7 @@ struct ftrace_buffer_info { #ifdef CONFIG_TRACER_SNAPSHOT static int tracing_snapshot_open(struct inode *inode, struct file *file) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; struct seq_file *m; int ret = 0; @@ -4690,7 +4685,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) return -ENODEV; if (file->f_mode & FMODE_READ) { - iter = __tracing_open(tr, tc, inode, file, true); + iter = __tracing_open(inode, file, true); if (IS_ERR(iter)) ret = PTR_ERR(iter); } else { @@ -4707,8 +4702,8 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) ret = 0; iter->tr = tr; - iter->trace_buffer = &tc->tr->max_buffer; - iter->cpu_file = tc->cpu; + iter->trace_buffer = &tr->max_buffer; + iter->cpu_file = tracing_get_cpu(inode); m->private = iter; file->private_data = m; } @@ -5525,7 +5520,6 @@ trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent, static void tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) { - struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu); struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu); struct dentry *d_cpu; char cpu_dir[30]; /* 30 characters should be more than enough */ @@ -5546,7 +5540,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) /* per cpu trace */ trace_create_cpu_file("trace", 0644, d_cpu, - &data->trace_cpu, cpu, &tracing_fops); + tr, cpu, &tracing_fops); trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu, tr, cpu, &tracing_buffers_fops); @@ -5559,7 +5553,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) #ifdef CONFIG_TRACER_SNAPSHOT trace_create_cpu_file("snapshot", 0644, d_cpu, - &data->trace_cpu, cpu, &snapshot_fops); + tr, cpu, &snapshot_fops); trace_create_cpu_file("snapshot_raw", 0444, d_cpu, tr, cpu, &snapshot_raw_fops); @@ -6125,7 +6119,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) tr, &tracing_iter_fops); trace_create_file("trace", 0644, d_tracer, - (void *)&tr->trace_cpu, &tracing_fops); + tr, &tracing_fops); trace_create_file("trace_pipe", 0444, d_tracer, tr, &tracing_pipe_fops); @@ -6146,11 +6140,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) &trace_clock_fops); trace_create_file("tracing_on", 0644, d_tracer, - tr, &rb_simple_fops); + tr, &rb_simple_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_file("snapshot", 0644, d_tracer, - (void *)&tr->trace_cpu, &snapshot_fops); + tr, &snapshot_fops); #endif for_each_tracing_cpu(cpu) |