The patch below does not apply to the 6.16-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-6.16.y git checkout FETCH_HEAD git cherry-pick -x 017ef1228d735965419ff118fe1b89089e772c42 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025082107-shortcut-trough-dbf3@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 017ef1228d735965419ff118fe1b89089e772c42 Mon Sep 17 00:00:00 2001 From: Shuicheng Lin shuicheng.lin@intel.com Date: Mon, 7 Jul 2025 00:49:14 +0000 Subject: [PATCH] drm/xe: Release runtime pm for error path of xe_devcoredump_read()

xe_pm_runtime_put() is missed to be called for the error path in xe_devcoredump_read(). Add function description comments for xe_devcoredump_read() to help understand it.

v2: more detail function comments and refine goto logic (Matt)

Fixes: c4a2e5f865b7 ("drm/xe: Add devcoredump chunking") Cc: stable@vger.kernel.org Reviewed-by: Matthew Brost matthew.brost@intel.com Signed-off-by: Shuicheng Lin shuicheng.lin@intel.com Signed-off-by: Matthew Brost matthew.brost@intel.com Link: https://lore.kernel.org/r/20250707004911.3502904-6-shuicheng.lin@intel.com

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c index 94625010abc4..203e3038cc81 100644 --- a/drivers/gpu/drm/xe/xe_devcoredump.c +++ b/drivers/gpu/drm/xe/xe_devcoredump.c @@ -171,14 +171,32 @@ static void xe_devcoredump_snapshot_free(struct xe_devcoredump_snapshot *ss)

#define XE_DEVCOREDUMP_CHUNK_MAX (SZ_512M + SZ_1G)

+/** + * xe_devcoredump_read() - Read data from the Xe device coredump snapshot + * @buffer: Destination buffer to copy the coredump data into + * @offset: Offset in the coredump data to start reading from + * @count: Number of bytes to read + * @data: Pointer to the xe_devcoredump structure + * @datalen: Length of the data (unused) + * + * Reads a chunk of the coredump snapshot data into the provided buffer. + * If the devcoredump is smaller than 1.5 GB (XE_DEVCOREDUMP_CHUNK_MAX), + * it is read directly from a pre-written buffer. For larger devcoredumps, + * the pre-written buffer must be periodically repopulated from the snapshot + * state due to kmalloc size limitations. + * + * Return: Number of bytes copied on success, or a negative error code on failure. + */ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset, size_t count, void *data, size_t datalen) { struct xe_devcoredump *coredump = data; struct xe_devcoredump_snapshot *ss; - ssize_t byte_copied; + ssize_t byte_copied = 0; u32 chunk_offset; ssize_t new_chunk_position; + bool pm_needed = false; + int ret = 0;

if (!coredump) return -ENODEV; @@ -188,20 +206,19 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset, /* Ensure delayed work is captured before continuing */ flush_work(&ss->work);

- if (ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX) + pm_needed = ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX; + if (pm_needed) xe_pm_runtime_get(gt_to_xe(ss->gt));

mutex_lock(&coredump->lock);

if (!ss->read.buffer) { - mutex_unlock(&coredump->lock); - return -ENODEV; + ret = -ENODEV; + goto unlock; }

- if (offset >= ss->read.size) { - mutex_unlock(&coredump->lock); - return 0; - } + if (offset >= ss->read.size) + goto unlock;

new_chunk_position = div_u64_rem(offset, XE_DEVCOREDUMP_CHUNK_MAX, @@ -221,12 +238,13 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset, ss->read.size - offset; memcpy(buffer, ss->read.buffer + chunk_offset, byte_copied);

+unlock: mutex_unlock(&coredump->lock);

- if (ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX) + if (pm_needed) xe_pm_runtime_put(gt_to_xe(ss->gt));

- return byte_copied; + return byte_copied ? byte_copied : ret; }

static void xe_devcoredump_free(void *data)