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authorLinus Torvalds <torvalds@linux-foundation.org>2021-11-11 19:16:33 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-11 19:16:33 +0100
commit600b18f88f2625ba48542dfeaa5fe8b23b3fd2c4 (patch)
tree585207bd9519f564384f3b3fa9a9c0fb2fa3f0fc /kernel
parentMerge tag 'net-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/net... (diff)
parentftrace/direct: Fix lockup in modify_ftrace_direct_multi (diff)
downloadlinux-600b18f88f2625ba48542dfeaa5fe8b23b3fd2c4.tar.xz
linux-600b18f88f2625ba48542dfeaa5fe8b23b3fd2c4.zip
Merge tag 'trace-v5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt: "Two locking fixes: - Add mutex protection to ring_buffer_reset() - Fix deadlock in modify_ftrace_direct_multi()" * tag 'trace-v5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace/direct: Fix lockup in modify_ftrace_direct_multi ring-buffer: Protect ring_buffer_reset() from reentrancy
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c3
-rw-r--r--kernel/trace/ring_buffer.c5
2 files changed, 7 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 007a3ded0358..30bc880c3849 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5602,10 +5602,11 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
}
}
+ mutex_unlock(&ftrace_lock);
+
/* Removing the tmp_ops will add the updated direct callers to the functions */
unregister_ftrace_function(&tmp_ops);
- mutex_unlock(&ftrace_lock);
out_direct:
mutex_unlock(&direct_mutex);
return err;
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f6520d0a4c8c..2699e9e562b1 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -5228,6 +5228,9 @@ void ring_buffer_reset(struct trace_buffer *buffer)
struct ring_buffer_per_cpu *cpu_buffer;
int cpu;
+ /* prevent another thread from changing buffer sizes */
+ mutex_lock(&buffer->mutex);
+
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
@@ -5246,6 +5249,8 @@ void ring_buffer_reset(struct trace_buffer *buffer)
atomic_dec(&cpu_buffer->record_disabled);
atomic_dec(&cpu_buffer->resize_disabled);
}
+
+ mutex_unlock(&buffer->mutex);
}
EXPORT_SYMBOL_GPL(ring_buffer_reset);