6.12-stable review patch. If anyone has any objections, please let me know.
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From: Lucas De Marchi lucas.demarchi@intel.com
[ Upstream commit d7b028656c29b22fcde1c6ee1df5b28fbba987b5 ]
That pool implementation doesn't really work: if the krealloc happens to move the memory and return another address, the entries in the xarray become invalid, leading to use-after-free later:
BUG: KASAN: slab-use-after-free in xe_reg_sr_apply_mmio+0x570/0x760 [xe] Read of size 4 at addr ffff8881244b2590 by task modprobe/2753
Allocated by task 2753: kasan_save_stack+0x39/0x70 kasan_save_track+0x14/0x40 kasan_save_alloc_info+0x37/0x60 __kasan_kmalloc+0xc3/0xd0 __kmalloc_node_track_caller_noprof+0x200/0x6d0 krealloc_noprof+0x229/0x380
Simplify the code to fix the bug. A better pooling strategy may be added back later if needed.
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Reviewed-by: Matt Roper matthew.d.roper@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20241209232739.147417-2-lucas.... Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com (cherry picked from commit e5283bd4dfecbd3335f43b62a68e24dae23f59e4) Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/xe/xe_reg_sr.c | 31 ++++++---------------------- drivers/gpu/drm/xe/xe_reg_sr_types.h | 6 ------ 2 files changed, 6 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_reg_sr.c b/drivers/gpu/drm/xe/xe_reg_sr.c index 440ac572f6e5..52969c090965 100644 --- a/drivers/gpu/drm/xe/xe_reg_sr.c +++ b/drivers/gpu/drm/xe/xe_reg_sr.c @@ -26,46 +26,27 @@ #include "xe_reg_whitelist.h" #include "xe_rtp_types.h"
-#define XE_REG_SR_GROW_STEP_DEFAULT 16 - static void reg_sr_fini(struct drm_device *drm, void *arg) { struct xe_reg_sr *sr = arg; + struct xe_reg_sr_entry *entry; + unsigned long reg; + + xa_for_each(&sr->xa, reg, entry) + kfree(entry);
xa_destroy(&sr->xa); - kfree(sr->pool.arr); - memset(&sr->pool, 0, sizeof(sr->pool)); }
int xe_reg_sr_init(struct xe_reg_sr *sr, const char *name, struct xe_device *xe) { xa_init(&sr->xa); - memset(&sr->pool, 0, sizeof(sr->pool)); - sr->pool.grow_step = XE_REG_SR_GROW_STEP_DEFAULT; sr->name = name;
return drmm_add_action_or_reset(&xe->drm, reg_sr_fini, sr); } EXPORT_SYMBOL_IF_KUNIT(xe_reg_sr_init);
-static struct xe_reg_sr_entry *alloc_entry(struct xe_reg_sr *sr) -{ - if (sr->pool.used == sr->pool.allocated) { - struct xe_reg_sr_entry *arr; - - arr = krealloc_array(sr->pool.arr, - ALIGN(sr->pool.allocated + 1, sr->pool.grow_step), - sizeof(*arr), GFP_KERNEL); - if (!arr) - return NULL; - - sr->pool.arr = arr; - sr->pool.allocated += sr->pool.grow_step; - } - - return &sr->pool.arr[sr->pool.used++]; -} - static bool compatible_entries(const struct xe_reg_sr_entry *e1, const struct xe_reg_sr_entry *e2) { @@ -111,7 +92,7 @@ int xe_reg_sr_add(struct xe_reg_sr *sr, return 0; }
- pentry = alloc_entry(sr); + pentry = kmalloc(sizeof(*pentry), GFP_KERNEL); if (!pentry) { ret = -ENOMEM; goto fail; diff --git a/drivers/gpu/drm/xe/xe_reg_sr_types.h b/drivers/gpu/drm/xe/xe_reg_sr_types.h index ad48a52b824a..ebe11f237fa2 100644 --- a/drivers/gpu/drm/xe/xe_reg_sr_types.h +++ b/drivers/gpu/drm/xe/xe_reg_sr_types.h @@ -20,12 +20,6 @@ struct xe_reg_sr_entry { };
struct xe_reg_sr { - struct { - struct xe_reg_sr_entry *arr; - unsigned int used; - unsigned int allocated; - unsigned int grow_step; - } pool; struct xarray xa; const char *name;