The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 7d660c9b2bc95107f90a9f4c4759be85309a6550 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023092020-recreate-account-e563@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

7d660c9b2bc9 ("tracing: Have tracing_max_latency inc the trace array ref count") 21ccc9cd7211 ("tracing: Disable "other" permission bits in the tracefs files") a955d7eac177 ("trace: Add timerlat tracer") bce29ac9ce0b ("trace: Add osnoise tracer") 6880c987e451 ("tracing: Add LATENCY_FS_NOTIFY to define if latency_fsnotify() is defined") 8fa826b7344d ("trace/hwlat: Implement the mode config option") f689e4f280b6 ("tracing: Define new ftrace event "func_repeats"") f2cc020d7876 ("tracing: Fix various typos in comments") 2d396cb3b126 ("tracing: Do not create "enable" or "filter" files for ftrace event subsystem") 0c02006e6f5b ("tracing: Inline tracing_gen_ctx_flags()") 36590c50b2d0 ("tracing: Merge irqflags + preempt counter.") 09c0796adf0c ("Merge tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7d660c9b2bc95107f90a9f4c4759be85309a6550 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" rostedt@goodmis.org Date: Wed, 6 Sep 2023 22:47:13 -0400 Subject: [PATCH] tracing: Have tracing_max_latency inc the trace array ref count

The tracing_max_latency file points to the trace_array max_latency field. For an instance, if the file is opened and the instance is deleted, reading or writing to the file will cause a use after free.

Up the ref count of the trace_array when tracing_max_latency is opened.

Link: https://lkml.kernel.org/r/20230907024803.666889383@goodmis.org Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Zheng Yejian zhengyejian1@huawei.com Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()") Tested-by: Linux Kernel Functional Testing lkft@linaro.org Tested-by: Naresh Kamboju naresh.kamboju@linaro.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0827037ee3b8..c8b8b4c6feaf 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1772,7 +1772,7 @@ static void trace_create_maxlat_file(struct trace_array *tr, init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq); tr->d_max_latency = trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, - d_tracer, &tr->max_latency, + d_tracer, tr, &tracing_max_lat_fops); }

@@ -1805,7 +1805,7 @@ void latency_fsnotify(struct trace_array *tr)

#define trace_create_maxlat_file(tr, d_tracer) \ trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \ - d_tracer, &tr->max_latency, &tracing_max_lat_fops) + d_tracer, tr, &tracing_max_lat_fops)

#endif

@@ -6717,14 +6717,18 @@ static ssize_t tracing_max_lat_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos); + struct trace_array *tr = filp->private_data; + + return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos); }

static ssize_t tracing_max_lat_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos); + struct trace_array *tr = filp->private_data; + + return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos); }

#endif @@ -7778,10 +7782,11 @@ static const struct file_operations tracing_thresh_fops = {

#ifdef CONFIG_TRACER_MAX_TRACE static const struct file_operations tracing_max_lat_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tr, .read = tracing_max_lat_read, .write = tracing_max_lat_write, .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, }; #endif