Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-04 04:06:26 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

ring-buffer: Make sure the spare sub buffer used for reads has same size

Browse Source 
Now that the ring buffer specifies the size of its sub buffers, they all
need to be the same size. When doing a read, a swap is done with a spare
page. Make sure they are the same size before doing the swap, otherwise
the read will fail.

Link: https://lore.kernel.org/linux-trace-kernel/20231219185629.763664788@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2023-12-19 13:54:22 -05:00
parent b81e03a249
commit 4e958db34f
1 changed files with 11 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/trace/trace.c
View File

@ -7582,6 +7582,7 @@ struct ftrace_buffer_info {
struct trace_iterator iter;
void *spare;
unsigned int spare_cpu;
unsigned int spare_size;
unsigned int read;
};
@ -8301,6 +8302,15 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
/* Make sure the spare matches the current sub buffer size */
if (info->spare) {
if (page_size != info->spare_size) {
ring_buffer_free_read_page(iter->array_buffer->buffer,
info->spare_cpu, info->spare);
info->spare = NULL;
}
}
if (!info->spare) {
info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
iter->cpu_file);
@ -8309,6 +8319,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
info->spare = NULL;
} else {
info->spare_cpu = iter->cpu_file;
info->spare_size = page_size;
}
}
if (!info->spare)