The patch below does not apply to the 6.13-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-6.13.y git checkout FETCH_HEAD git cherry-pick -x e379856b428acafb8ed689f31d65814da6447b2e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025040916-appraiser-chute-b24d@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From e379856b428acafb8ed689f31d65814da6447b2e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Adri=C3=A1n=20Larumbe?= adrian.larumbe@collabora.com Date: Mon, 3 Mar 2025 19:08:45 +0000 Subject: [PATCH] drm/panthor: Replace sleep locks with spinlocks in fdinfo path MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Commit 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo group samples") introduced an xarray lock to deal with potential use-after-free errors when accessing groups fdinfo figures. However, this toggles the kernel's atomic context status, so the next nested mutex lock will raise a warning when the kernel is compiled with mutex debug options:

CONFIG_DEBUG_RT_MUTEXES=y CONFIG_DEBUG_MUTEXES=y

Replace Panthor's group fdinfo data mutex with a guarded spinlock.

Signed-off-by: Adrián Larumbe adrian.larumbe@collabora.com Fixes: 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo group samples") Reviewed-by: Liviu Dudau liviu.dudau@arm.com Reviewed-by: Boris Brezillon boris.brezillon@collabora.com Reviewed-by: Steven Price steven.price@arm.com Signed-off-by: Steven Price steven.price@arm.com Link: https://patchwork.freedesktop.org/patch/msgid/20250303190923.1639985-1-adria...

diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 1a276db095ff..4d31d1967716 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -9,6 +9,7 @@ #include <drm/panthor_drm.h>

#include <linux/build_bug.h> +#include <linux/cleanup.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/dma-mapping.h> @@ -631,10 +632,10 @@ struct panthor_group { struct panthor_gpu_usage data;

/** - * @lock: Mutex to govern concurrent access from drm file's fdinfo callback - * and job post-completion processing function + * @fdinfo.lock: Spinlock to govern concurrent access from drm file's fdinfo + * callback and job post-completion processing function */ - struct mutex lock; + spinlock_t lock;

/** @fdinfo.kbo_sizes: Aggregate size of private kernel BO's held by the group. */ size_t kbo_sizes; @@ -910,8 +911,6 @@ static void group_release_work(struct work_struct *work) release_work); u32 i;

- mutex_destroy(&group->fdinfo.lock); - for (i = 0; i < group->queue_count; i++) group_free_queue(group, group->queues[i]);

@@ -2861,12 +2860,12 @@ static void update_fdinfo_stats(struct panthor_job *job) struct panthor_job_profiling_data *slots = queue->profiling.slots->kmap; struct panthor_job_profiling_data *data = &slots[job->profiling.slot];

- mutex_lock(&group->fdinfo.lock); - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) - fdinfo->cycles += data->cycles.after - data->cycles.before; - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) - fdinfo->time += data->time.after - data->time.before; - mutex_unlock(&group->fdinfo.lock); + scoped_guard(spinlock, &group->fdinfo.lock) { + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) + fdinfo->cycles += data->cycles.after - data->cycles.before; + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) + fdinfo->time += data->time.after - data->time.before; + } }

void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) @@ -2880,12 +2879,11 @@ void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile)

xa_lock(&gpool->xa); xa_for_each(&gpool->xa, i, group) { - mutex_lock(&group->fdinfo.lock); + guard(spinlock)(&group->fdinfo.lock); pfile->stats.cycles += group->fdinfo.data.cycles; pfile->stats.time += group->fdinfo.data.time; group->fdinfo.data.cycles = 0; group->fdinfo.data.time = 0; - mutex_unlock(&group->fdinfo.lock); } xa_unlock(&gpool->xa); } @@ -3537,7 +3535,7 @@ int panthor_group_create(struct panthor_file *pfile, mutex_unlock(&sched->reset.lock);

add_group_kbo_sizes(group->ptdev, group); - mutex_init(&group->fdinfo.lock); + spin_lock_init(&group->fdinfo.lock);

return gid;