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drm/xe: Fix potential deadlock in __fini_dbm

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If Doorbell Manager is in unclean state during fini phase, for
debug purposes we try to print it's state, but we missed the fact
that we are already holding a lock so the xe_guc_db_mgr_print()
will deadlock since it also attempts to grab the same lock.

Fixes: 587c73343ac7 ("drm/xe: Introduce GuC Doorbells Manager")
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://lore.kernel.org/r/20240111185603.673-1-michal.wajdeczko@intel.com
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
This commit is contained in:
Michal Wajdeczko 2024-01-11 19:56:03 +01:00
parent 33ff1f21bd
commit 1113e52ffe
1 changed files with 16 additions and 11 deletions
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27
drivers/gpu/drm/xe/xe_guc_db_mgr.c
View File

@ -46,6 +46,8 @@ static struct xe_device *dbm_to_xe(struct xe_guc_db_mgr *dbm)
#define dbm_assert(_dbm, _cond) xe_gt_assert(dbm_to_gt(_dbm), _cond)
#define dbm_mutex(_dbm) (&dbm_to_guc(_dbm)->submission_state.lock)
static void dbm_print_locked(struct xe_guc_db_mgr *dbm, struct drm_printer *p, int indent);
static void __fini_dbm(struct drm_device *drm, void *arg)
{
struct xe_guc_db_mgr *dbm = arg;
@ -59,7 +61,7 @@ static void __fini_dbm(struct drm_device *drm, void *arg)
xe_gt_err(dbm_to_gt(dbm), "GuC doorbells manager unclean (%u/%u)\n",
weight, dbm->count);
xe_guc_db_mgr_print(dbm, &p, 1);
dbm_print_locked(dbm, &p, 1);
}
bitmap_free(dbm->bitmap);
@ -219,14 +221,7 @@ void xe_guc_db_mgr_release_range(struct xe_guc_db_mgr *dbm,
mutex_unlock(dbm_mutex(dbm));
}
/**
* xe_guc_db_mgr_print() - Print status of GuC Doorbells Manager.
* @dbm: the &xe_guc_db_mgr to print
* @p: the &drm_printer to print to
* @indent: tab indentation level
*/
void xe_guc_db_mgr_print(struct xe_guc_db_mgr *dbm,
struct drm_printer *p, int indent)
static void dbm_print_locked(struct xe_guc_db_mgr *dbm, struct drm_printer *p, int indent)
{
unsigned int rs, re;
unsigned int total;
@ -235,8 +230,6 @@ void xe_guc_db_mgr_print(struct xe_guc_db_mgr *dbm,
if (!dbm->bitmap)
return;
mutex_lock(dbm_mutex(dbm));
total = 0;
for_each_clear_bitrange(rs, re, dbm->bitmap, dbm->count) {
drm_printf_indent(p, indent, "available range: %u..%u (%u)\n",
@ -252,7 +245,19 @@ void xe_guc_db_mgr_print(struct xe_guc_db_mgr *dbm,
total += re - rs;
}
drm_printf_indent(p, indent, "reserved total: %u\n", total);
}
/**
* xe_guc_db_mgr_print() - Print status of GuC Doorbells Manager.
* @dbm: the &xe_guc_db_mgr to print
* @p: the &drm_printer to print to
* @indent: tab indentation level
*/
void xe_guc_db_mgr_print(struct xe_guc_db_mgr *dbm,
struct drm_printer *p, int indent)
{
mutex_lock(dbm_mutex(dbm));
dbm_print_locked(dbm, p, indent);
mutex_unlock(dbm_mutex(dbm));
}