From: Jeevaka Prabu Badrappan jeevaka.badrappan@intel.com
[ Upstream commit 4ea512714c42c69828b4a2647d206bf404043ad5 ]
When an attribute group is created with sysfs_create_group() or sysfs_create_files() the ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() callback to kobj_attr_show(). kobj_attr_show() uses container_of() to get the ->show() callback from the attribute it was passed, meaning the ->show() callback needs to be the same type as the ->show() callback in 'struct kobj_attribute'.
However, cur_freq_show() has the type of the ->show() callback in 'struct device_attribute', which causes a CFI violation when opening the 'id' sysfs node under gtidle/freq/throttle. This happens to work because the layout of 'struct kobj_attribute' and 'struct device_attribute' are the same, so the container_of() cast happens to allow the ->show() callback to still work.
Changed the type of cur_freq_show() and few more functions to match the ->show() callback in 'struct kobj_attributes' to resolve the CFI violation.
CFI failure seen while accessing sysfs files under /sys/class/drm/card0/device/tile0/gt*/gtidle/* /sys/class/drm/card0/device/tile0/gt*/freq0/* /sys/class/drm/card0/device/tile0/gt*/freq0/throttle/*
[ 2599.618075] RIP: 0010:__cfi_cur_freq_show+0xd/0x10 [xe] [ 2599.624452] Code: 44 c1 44 89 fa e8 03 95 39 f2 48 98 5b 41 5e 41 5f 5d c3 c9 [ 2599.646638] RSP: 0018:ffffbe438ead7d10 EFLAGS: 00010286 [ 2599.652823] RAX: ffff9f7d8b3845d8 RBX: ffff9f7dee8c95d8 RCX: 0000000000000000 [ 2599.661246] RDX: ffff9f7e6f439000 RSI: ffffffffc13ada30 RDI: ffff9f7d975d4b00 [ 2599.669669] RBP: ffffbe438ead7d18 R08: 0000000000001000 R09: ffff9f7e6f439000 [ 2599.678092] R10: 00000000e07304a6 R11: ffffffffc1241ca0 R12: ffffffffb4836ea0 [ 2599.688435] R13: ffff9f7e45fb1180 R14: ffff9f7d975d4b00 R15: ffff9f7e6f439000 [ 2599.696860] FS: 000076b02b66cfc0(0000) GS:ffff9f80ef400000(0000) knlGS:00000 [ 2599.706412] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2599.713196] CR2: 00005f80d94641a9 CR3: 00000001e44ec006 CR4: 0000000100f72ef0 [ 2599.721618] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2599.730041] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 [ 2599.738464] PKRU: 55555554 [ 2599.741655] Call Trace: [ 2599.744541] <TASK> [ 2599.747017] ? __die_body+0x69/0xb0 [ 2599.751151] ? die+0xa9/0xd0 [ 2599.754548] ? do_trap+0x89/0x160 [ 2599.758476] ? __cfi_cur_freq_show+0xd/0x10 [xe b37985c94829727668bd7c5b33c1] [ 2599.768315] ? handle_invalid_op+0x69/0x90 [ 2599.773167] ? __cfi_cur_freq_show+0xd/0x10 [xe b37985c94829727668bd7c5b33c1] [ 2599.783010] ? exc_invalid_op+0x36/0x60 [ 2599.787552] ? fred_hwexc+0x123/0x1a0 [ 2599.791873] ? fred_entry_from_kernel+0x7b/0xd0 [ 2599.797219] ? asm_fred_entrypoint_kernel+0x45/0x70 [ 2599.802976] ? act_freq_show+0x70/0x70 [xe b37985c94829727668bd7c5b33c1d9998] [ 2599.812301] ? __cfi_cur_freq_show+0xd/0x10 [xe b37985c94829727668bd7c5b33c1] [ 2599.822137] ? __kmalloc_node_noprof+0x1f3/0x420 [ 2599.827594] ? __kvmalloc_node_noprof+0xcb/0x180 [ 2599.833045] ? kobj_attr_show+0x22/0x40 [ 2599.837571] sysfs_kf_seq_show+0xa8/0x110 [ 2599.842302] kernfs_seq_show+0x38/0x50
Signed-off-by: Jeevaka Prabu Badrappan jeevaka.badrappan@intel.com Reviewed-by: Rodrigo Vivi rodrigo.vivi@intel.com Link: https://lore.kernel.org/r/20250422171852.85558-1-jeevaka.badrappan@intel.com Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Signed-off-by: Sasha Levin sashal@kernel.org ---
**YES** This commit should be backported to stable kernel trees for the following reasons: ## Primary Analysis **1. Important Bug Fix for Security Feature** The commit fixes Control Flow Integrity (CFI) violations in the xe driver's sysfs interface. CFI is a critical security feature in modern kernels that prevents function pointer hijacking attacks. CFI violations can cause: - System crashes when accessing sysfs files (as shown in the stack trace) - Potential security vulnerabilities if exploited - Poor user experience when monitoring GPU frequency/throttling through sysfs **2. Small, Contained Fix with Clear Impact** The changes are purely type safety fixes that: - Convert `struct device_attribute` callbacks to `struct kobj_attribute` callbacks across 3 files - Change function signatures from `(struct device *dev, struct device_attribute *attr, char *buf)` to `(struct kobject *kobj, struct kobj_attribute *attr, char *buf)` - Update attribute definitions from `DEVICE_ATTR_RO/RW` to `__ATTR_RO/RW` with proper kobj_attribute types - Add `struct device *dev = kobj_to_dev(kobj);` calls to maintain functionality **3. Pattern Matches Successful Backports** This commit follows the exact same pattern as Similar Commits #3-#5 (all marked "Backport Status: YES"): - ACPI platform-profile CFI fix (commit 2e6674dfefd8) - already backported - Intel uncore-frequency CFI fix - ACPI bgrt CFI fix All these commits fix the same fundamental issue: mismatched function pointer types when sysfs groups are created with `sysfs_create_group()` vs `device_create_file()`. **4. Driver Availability and Kernel Version Context** The xe driver was introduced in kernel 6.10, which means: - This fix is relevant for stable trees 6.10+ - The affected code exists in current stable kernels - Users with Intel discrete GPUs (Tiger Lake+) would encounter this bug **5. Low Risk, High Value** - **Zero functional changes** - same behavior, just type-safe - **No architectural changes** - purely corrective - **Self- contained** - only affects xe driver sysfs interface - **Clear error symptoms** - CFI failures with specific stack traces make issues obvious - **High user impact** - prevents crashes when monitoring GPU performance **6. Meets Stable Tree Criteria** - ✅ Fixes important bugs affecting users (CFI crashes) - ✅ Small and contained (type signature changes only) - ✅ No clear side effects beyond fixing the issue - ✅ No major architectural changes - ✅ Confined to xe subsystem - ✅ Minimal regression risk The code changes in `xe_gt_freq.c`, `xe_gt_idle.c`, and `xe_gt_throttle.c` are straightforward type corrections that maintain identical functionality while ensuring CFI compliance. This is exactly the type of safety/correctness fix that stable trees should include.
drivers/gpu/drm/xe/xe_gt_freq.c | 82 ++++++++++++++------------ drivers/gpu/drm/xe/xe_gt_idle.c | 28 +++++---- drivers/gpu/drm/xe/xe_gt_throttle.c | 90 ++++++++++++++--------------- 3 files changed, 107 insertions(+), 93 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_gt_freq.c b/drivers/gpu/drm/xe/xe_gt_freq.c index 604bdc7c81736..868a5d2c1a52f 100644 --- a/drivers/gpu/drm/xe/xe_gt_freq.c +++ b/drivers/gpu/drm/xe/xe_gt_freq.c @@ -56,9 +56,10 @@ dev_to_xe(struct device *dev) return gt_to_xe(kobj_to_gt(dev->kobj.parent)); }
-static ssize_t act_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t act_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq;
@@ -68,11 +69,12 @@ static ssize_t act_freq_show(struct device *dev,
return sysfs_emit(buf, "%d\n", freq); } -static DEVICE_ATTR_RO(act_freq); +static struct kobj_attribute attr_act_freq = __ATTR_RO(act_freq);
-static ssize_t cur_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t cur_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq; ssize_t ret; @@ -85,11 +87,12 @@ static ssize_t cur_freq_show(struct device *dev,
return sysfs_emit(buf, "%d\n", freq); } -static DEVICE_ATTR_RO(cur_freq); +static struct kobj_attribute attr_cur_freq = __ATTR_RO(cur_freq);
-static ssize_t rp0_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t rp0_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq;
@@ -99,11 +102,12 @@ static ssize_t rp0_freq_show(struct device *dev,
return sysfs_emit(buf, "%d\n", freq); } -static DEVICE_ATTR_RO(rp0_freq); +static struct kobj_attribute attr_rp0_freq = __ATTR_RO(rp0_freq);
-static ssize_t rpe_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t rpe_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq;
@@ -113,11 +117,12 @@ static ssize_t rpe_freq_show(struct device *dev,
return sysfs_emit(buf, "%d\n", freq); } -static DEVICE_ATTR_RO(rpe_freq); +static struct kobj_attribute attr_rpe_freq = __ATTR_RO(rpe_freq);
-static ssize_t rpa_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t rpa_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq;
@@ -127,20 +132,22 @@ static ssize_t rpa_freq_show(struct device *dev,
return sysfs_emit(buf, "%d\n", freq); } -static DEVICE_ATTR_RO(rpa_freq); +static struct kobj_attribute attr_rpa_freq = __ATTR_RO(rpa_freq);
-static ssize_t rpn_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t rpn_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev);
return sysfs_emit(buf, "%d\n", xe_guc_pc_get_rpn_freq(pc)); } -static DEVICE_ATTR_RO(rpn_freq); +static struct kobj_attribute attr_rpn_freq = __ATTR_RO(rpn_freq);
-static ssize_t min_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t min_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq; ssize_t ret; @@ -154,9 +161,10 @@ static ssize_t min_freq_show(struct device *dev, return sysfs_emit(buf, "%d\n", freq); }
-static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, - const char *buff, size_t count) +static ssize_t min_freq_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buff, size_t count) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq; ssize_t ret; @@ -173,11 +181,12 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
return count; } -static DEVICE_ATTR_RW(min_freq); +static struct kobj_attribute attr_min_freq = __ATTR_RW(min_freq);
-static ssize_t max_freq_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t max_freq_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq; ssize_t ret; @@ -191,9 +200,10 @@ static ssize_t max_freq_show(struct device *dev, return sysfs_emit(buf, "%d\n", freq); }
-static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, - const char *buff, size_t count) +static ssize_t max_freq_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buff, size_t count) { + struct device *dev = kobj_to_dev(kobj); struct xe_guc_pc *pc = dev_to_pc(dev); u32 freq; ssize_t ret; @@ -210,17 +220,17 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
return count; } -static DEVICE_ATTR_RW(max_freq); +static struct kobj_attribute attr_max_freq = __ATTR_RW(max_freq);
static const struct attribute *freq_attrs[] = { - &dev_attr_act_freq.attr, - &dev_attr_cur_freq.attr, - &dev_attr_rp0_freq.attr, - &dev_attr_rpa_freq.attr, - &dev_attr_rpe_freq.attr, - &dev_attr_rpn_freq.attr, - &dev_attr_min_freq.attr, - &dev_attr_max_freq.attr, + &attr_act_freq.attr, + &attr_cur_freq.attr, + &attr_rp0_freq.attr, + &attr_rpa_freq.attr, + &attr_rpe_freq.attr, + &attr_rpn_freq.attr, + &attr_min_freq.attr, + &attr_max_freq.attr, NULL };
diff --git a/drivers/gpu/drm/xe/xe_gt_idle.c b/drivers/gpu/drm/xe/xe_gt_idle.c index fbbace7b0b12a..c11206410a4d4 100644 --- a/drivers/gpu/drm/xe/xe_gt_idle.c +++ b/drivers/gpu/drm/xe/xe_gt_idle.c @@ -249,9 +249,10 @@ int xe_gt_idle_pg_print(struct xe_gt *gt, struct drm_printer *p) return 0; }
-static ssize_t name_show(struct device *dev, - struct device_attribute *attr, char *buff) +static ssize_t name_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt_idle *gtidle = dev_to_gtidle(dev); struct xe_guc_pc *pc = gtidle_to_pc(gtidle); ssize_t ret; @@ -262,11 +263,12 @@ static ssize_t name_show(struct device *dev,
return ret; } -static DEVICE_ATTR_RO(name); +static struct kobj_attribute name_attr = __ATTR_RO(name);
-static ssize_t idle_status_show(struct device *dev, - struct device_attribute *attr, char *buff) +static ssize_t idle_status_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt_idle *gtidle = dev_to_gtidle(dev); struct xe_guc_pc *pc = gtidle_to_pc(gtidle); enum xe_gt_idle_state state; @@ -277,6 +279,7 @@ static ssize_t idle_status_show(struct device *dev,
return sysfs_emit(buff, "%s\n", gt_idle_state_to_string(state)); } +static struct kobj_attribute idle_status_attr = __ATTR_RO(idle_status);
u64 xe_gt_idle_residency_msec(struct xe_gt_idle *gtidle) { @@ -291,10 +294,11 @@ u64 xe_gt_idle_residency_msec(struct xe_gt_idle *gtidle) return residency; }
-static DEVICE_ATTR_RO(idle_status); -static ssize_t idle_residency_ms_show(struct device *dev, - struct device_attribute *attr, char *buff) + +static ssize_t idle_residency_ms_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt_idle *gtidle = dev_to_gtidle(dev); struct xe_guc_pc *pc = gtidle_to_pc(gtidle); u64 residency; @@ -305,12 +309,12 @@ static ssize_t idle_residency_ms_show(struct device *dev,
return sysfs_emit(buff, "%llu\n", residency); } -static DEVICE_ATTR_RO(idle_residency_ms); +static struct kobj_attribute idle_residency_attr = __ATTR_RO(idle_residency_ms);
static const struct attribute *gt_idle_attrs[] = { - &dev_attr_name.attr, - &dev_attr_idle_status.attr, - &dev_attr_idle_residency_ms.attr, + &name_attr.attr, + &idle_status_attr.attr, + &idle_residency_attr.attr, NULL, };
diff --git a/drivers/gpu/drm/xe/xe_gt_throttle.c b/drivers/gpu/drm/xe/xe_gt_throttle.c index 8db78d616b6f2..aa962c783cdf7 100644 --- a/drivers/gpu/drm/xe/xe_gt_throttle.c +++ b/drivers/gpu/drm/xe/xe_gt_throttle.c @@ -114,115 +114,115 @@ static u32 read_reason_vr_tdc(struct xe_gt *gt) return tdc; }
-static ssize_t status_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t status_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool status = !!read_status(gt);
return sysfs_emit(buff, "%u\n", status); } -static DEVICE_ATTR_RO(status); +static struct kobj_attribute attr_status = __ATTR_RO(status);
-static ssize_t reason_pl1_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_pl1_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool pl1 = !!read_reason_pl1(gt);
return sysfs_emit(buff, "%u\n", pl1); } -static DEVICE_ATTR_RO(reason_pl1); +static struct kobj_attribute attr_reason_pl1 = __ATTR_RO(reason_pl1);
-static ssize_t reason_pl2_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_pl2_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool pl2 = !!read_reason_pl2(gt);
return sysfs_emit(buff, "%u\n", pl2); } -static DEVICE_ATTR_RO(reason_pl2); +static struct kobj_attribute attr_reason_pl2 = __ATTR_RO(reason_pl2);
-static ssize_t reason_pl4_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_pl4_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool pl4 = !!read_reason_pl4(gt);
return sysfs_emit(buff, "%u\n", pl4); } -static DEVICE_ATTR_RO(reason_pl4); +static struct kobj_attribute attr_reason_pl4 = __ATTR_RO(reason_pl4);
-static ssize_t reason_thermal_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_thermal_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool thermal = !!read_reason_thermal(gt);
return sysfs_emit(buff, "%u\n", thermal); } -static DEVICE_ATTR_RO(reason_thermal); +static struct kobj_attribute attr_reason_thermal = __ATTR_RO(reason_thermal);
-static ssize_t reason_prochot_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_prochot_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool prochot = !!read_reason_prochot(gt);
return sysfs_emit(buff, "%u\n", prochot); } -static DEVICE_ATTR_RO(reason_prochot); +static struct kobj_attribute attr_reason_prochot = __ATTR_RO(reason_prochot);
-static ssize_t reason_ratl_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_ratl_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool ratl = !!read_reason_ratl(gt);
return sysfs_emit(buff, "%u\n", ratl); } -static DEVICE_ATTR_RO(reason_ratl); +static struct kobj_attribute attr_reason_ratl = __ATTR_RO(reason_ratl);
-static ssize_t reason_vr_thermalert_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_vr_thermalert_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool thermalert = !!read_reason_vr_thermalert(gt);
return sysfs_emit(buff, "%u\n", thermalert); } -static DEVICE_ATTR_RO(reason_vr_thermalert); +static struct kobj_attribute attr_reason_vr_thermalert = __ATTR_RO(reason_vr_thermalert);
-static ssize_t reason_vr_tdc_show(struct device *dev, - struct device_attribute *attr, - char *buff) +static ssize_t reason_vr_tdc_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buff) { + struct device *dev = kobj_to_dev(kobj); struct xe_gt *gt = dev_to_gt(dev); bool tdc = !!read_reason_vr_tdc(gt);
return sysfs_emit(buff, "%u\n", tdc); } -static DEVICE_ATTR_RO(reason_vr_tdc); +static struct kobj_attribute attr_reason_vr_tdc = __ATTR_RO(reason_vr_tdc);
static struct attribute *throttle_attrs[] = { - &dev_attr_status.attr, - &dev_attr_reason_pl1.attr, - &dev_attr_reason_pl2.attr, - &dev_attr_reason_pl4.attr, - &dev_attr_reason_thermal.attr, - &dev_attr_reason_prochot.attr, - &dev_attr_reason_ratl.attr, - &dev_attr_reason_vr_thermalert.attr, - &dev_attr_reason_vr_tdc.attr, + &attr_status.attr, + &attr_reason_pl1.attr, + &attr_reason_pl2.attr, + &attr_reason_pl4.attr, + &attr_reason_thermal.attr, + &attr_reason_prochot.attr, + &attr_reason_ratl.attr, + &attr_reason_vr_thermalert.attr, + &attr_reason_vr_tdc.attr, NULL };