October 2023 - Linux-stable-mirror

[PATCH v7 0/5] mfd: tps6586x: register restart handler

by Benjamin Bara

Hi! The Tegra20 requires an enabled VDE power domain during startup. As the VDE is currently not used, it is disabled during runtime. Since 8f0c714ad9be, there is a workaround for the "normal restart path" which enables the VDE before doing PMC's warm reboot. This workaround is not executed in the "emergency restart path", leading to a hang-up during start. This series implements and registers a new pmic-based restart handler for boards with tps6586x. This cold reboot ensures that the VDE power domain is enabled during startup on tegra20-based boards. Since bae1d3a05a8b, i2c transfers are non-atomic while preemption is disabled (which is e.g. done during panic()). This could lead to warnings ("Voluntary context switch within RCU") in i2c-based restart handlers during emergency restart. The state of preemption should be detected by i2c_in_atomic_xfer_mode() to use atomic i2c xfer when required. Beside the new system_state check, the check is the same as the one pre v5.2. --- v7: - 5/5: drop mode check (suggested by Dmitry) - Link to v6: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v6-0-af44a4cd82e9@skid… v6: - drop 4/6 to abort restart on unexpected failure (suggested by Dmitry) - 4,5: fix comments in handlers (suggested by Lee) - 4,5: same delay for both handlers (suggested by Lee) v5: - introduce new 3 & 4, therefore 3 -> 5, 4 -> 6 - 3: provide dev to sys_off handler, if it is known - 4: return NOTIFY_DONE from sys_off_notify, to avoid skipping - 5: drop Reviewed-by from Dmitry, add poweroff timeout - 5,6: return notifier value instead of direct errno from handler - 5,6: use new dev field instead of passing dev as cb_data - 5,6: increase timeout values based on error observations - 6: skip unsupported reboot modes in restart handler --- Benjamin Bara (5): kernel/reboot: emergency_restart: set correct system_state i2c: core: run atomic i2c xfer when !preemptible kernel/reboot: add device to sys_off_handler mfd: tps6586x: use devm-based power off handler mfd: tps6586x: register restart handler drivers/i2c/i2c-core.h | 2 +- drivers/mfd/tps6586x.c | 50 ++++++++++++++++++++++++++++++++++++++++++-------- include/linux/reboot.h | 3 +++ kernel/reboot.c | 4 ++++ 4 files changed, 50 insertions(+), 9 deletions(-) --- base-commit: 197b6b60ae7bc51dd0814953c562833143b292aa change-id: 20230327-tegra-pmic-reboot-4175ff814a4b Best regards, -- Benjamin Bara <benjamin.bara(a)skidata.com>

1 year

6
19
0 0

[PATCH] SELinux: Check correct permissions for FS_IOC32_*

by Alfred Piccioni

Some ioctl commands do not require ioctl permission, but are routed to other permissions such as FILE_GETATTR or FILE_SETATTR. This routing is done by comparing the ioctl cmd to a set of 64-bit flags (FS_IOC_*). However, if a 32-bit process is running on a 64-bit kernel, it emmits 32-bit flags (FS_IOC32_*) for certain ioctl operations. These flags are being checked erroneoulsy, which leads to these ioctl operations being routed to the ioctl permission, rather than the correct file permissions. Two possible solutions exist: - Trim parameter "cmd" to a u16 so that only the last two bytes are checked in the case statement. - Explicitily add the FS_IOC32_* codes to the case statement. Solution 2 was chosen because it is a minimal explicit change. Solution 1 is a more elegant change, but is less explicit, as the switch statement appears to only check the FS_IOC_* codes upon first reading. Fixes: 0b24dcb7f2f7 ("Revert "selinux: simplify ioctl checking"") Signed-off-by: Alfred Piccioni <alpic(a)google.com> --- security/selinux/hooks.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d06e350fedee..bba83f437a1d 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3644,11 +3644,15 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd, case FIGETBSZ: case FS_IOC_GETFLAGS: case FS_IOC_GETVERSION: + case FS_IOC32_GETFLAGS: + case FS_IOC32_GETVERSION: error = file_has_perm(cred, file, FILE__GETATTR); break; case FS_IOC_SETFLAGS: case FS_IOC_SETVERSION: + case FS_IOC32_SETFLAGS: + case FS_IOC32_SETVERSION: error = file_has_perm(cred, file, FILE__SETATTR); break; base-commit: 50a510a78287c15cee644f345ef8bac8977986a7 -- 2.42.0.283.g2d96d420d3-goog

1 year

8
29
0 0

[PATCH] drm/vmwgfx: Keep a gem reference to user bos in surfaces

by Zack Rusin

From: Zack Rusin <zackr(a)vmware.com> Surfaces can be backed (i.e. stored in) memory objects (mob's) which are created and managed by the userspace as GEM buffers. Surfaces grab only a ttm reference which means that the gem object can be deleted underneath us, especially in cases where prime buffer export is used. Make sure that all userspace surfaces which are backed by gem objects hold a gem reference to make sure they're not deleted before vmw surfaces are done with them, which fixes: ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 2 PID: 2632 at lib/refcount.c:28 refcount_warn_saturate+0xfb/0x150 Modules linked in: overlay vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock snd_ens1371 snd_ac97_codec ac97_bus snd_pcm gameport> CPU: 2 PID: 2632 Comm: vmw_ref_count Not tainted 6.5.0-rc2-vmwgfx #1 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 RIP: 0010:refcount_warn_saturate+0xfb/0x150 Code: eb 9e 0f b6 1d 8b 5b a6 01 80 fb 01 0f 87 ba e4 80 00 83 e3 01 75 89 48 c7 c7 c0 3c f9 a3 c6 05 6f 5b a6 01 01 e8 15 81 98 ff <0f> 0b e9 6f ff ff ff 0f b> RSP: 0018:ffffbdc34344bba0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000027 RDX: ffff960475ea1548 RSI: 0000000000000001 RDI: ffff960475ea1540 RBP: ffffbdc34344bba8 R08: 0000000000000003 R09: 65646e75203a745f R10: ffffffffa5b32b20 R11: 72657466612d6573 R12: ffff96037d6a6400 R13: ffff9603484805b0 R14: 000000000000000b R15: ffff9603bed06060 FS: 00007f5fd8520c40(0000) GS:ffff960475e80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5fda755000 CR3: 000000010d012005 CR4: 00000000003706e0 Call Trace: <TASK> ? show_regs+0x6e/0x80 ? refcount_warn_saturate+0xfb/0x150 ? __warn+0x91/0x150 ? refcount_warn_saturate+0xfb/0x150 ? report_bug+0x19d/0x1b0 ? handle_bug+0x46/0x80 ? exc_invalid_op+0x1d/0x80 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xfb/0x150 drm_gem_object_handle_put_unlocked+0xba/0x110 [drm] drm_gem_object_release_handle+0x6e/0x80 [drm] drm_gem_handle_delete+0x6a/0xc0 [drm] ? __pfx_vmw_bo_unref_ioctl+0x10/0x10 [vmwgfx] vmw_bo_unref_ioctl+0x33/0x40 [vmwgfx] drm_ioctl_kernel+0xbc/0x160 [drm] drm_ioctl+0x2d2/0x580 [drm] ? __pfx_vmw_bo_unref_ioctl+0x10/0x10 [vmwgfx] ? do_vmi_munmap+0xee/0x180 vmw_generic_ioctl+0xbd/0x180 [vmwgfx] vmw_unlocked_ioctl+0x19/0x20 [vmwgfx] __x64_sys_ioctl+0x99/0xd0 do_syscall_64+0x5d/0x90 ? syscall_exit_to_user_mode+0x2a/0x50 ? do_syscall_64+0x6d/0x90 ? handle_mm_fault+0x16e/0x2f0 ? exit_to_user_mode_prepare+0x34/0x170 ? irqentry_exit_to_user_mode+0xd/0x20 ? irqentry_exit+0x3f/0x50 ? exc_page_fault+0x8e/0x190 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f5fda51aaff Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 7> RSP: 002b:00007ffd536a4d30 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffd536a4de0 RCX: 00007f5fda51aaff RDX: 00007ffd536a4de0 RSI: 0000000040086442 RDI: 0000000000000003 RBP: 0000000040086442 R08: 000055fa603ada50 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffd536a51b8 R13: 0000000000000003 R14: 000055fa5ebb4c80 R15: 00007f5fda90f040 </TASK> ---[ end trace 0000000000000000 ]--- A lot of the analyis on the bug was done by Murray McAllister and Ian Forbes. Reported-by: Murray McAllister <murray.mcallister(a)gmail.com> Cc: Ian Forbes <iforbes(a)vmware.com> Signed-off-by: Zack Rusin <zackr(a)vmware.com> Fixes: a950b989ea29 ("drm/vmwgfx: Do not drop the reference to the handle too soon") Cc: <stable(a)vger.kernel.org> # v6.2+ --- drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 7 +++--- drivers/gpu/drm/vmwgfx/vmwgfx_bo.h | 17 +++++++++---- drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c | 6 ++--- drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 4 +++ drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 10 +++++--- drivers/gpu/drm/vmwgfx/vmwgfx_gem.c | 18 +++++++++++--- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 6 ++--- drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c | 2 +- drivers/gpu/drm/vmwgfx/vmwgfx_resource.c | 12 ++++----- drivers/gpu/drm/vmwgfx/vmwgfx_shader.c | 4 +-- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 31 +++++++++--------------- 11 files changed, 68 insertions(+), 49 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c index c43853597776..2bfac3aad7b7 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c @@ -34,6 +34,8 @@ static void vmw_bo_release(struct vmw_bo *vbo) { + WARN_ON(vbo->tbo.base.funcs && + kref_read(&vbo->tbo.base.refcount) != 0); vmw_bo_unmap(vbo); drm_gem_object_release(&vbo->tbo.base); } @@ -497,7 +499,7 @@ static int vmw_user_bo_synccpu_release(struct drm_file *filp, if (!(flags & drm_vmw_synccpu_allow_cs)) { atomic_dec(&vmw_bo->cpu_writers); } - vmw_user_bo_unref(vmw_bo); + vmw_user_bo_unref(&vmw_bo); } return ret; @@ -539,7 +541,7 @@ int vmw_user_bo_synccpu_ioctl(struct drm_device *dev, void *data, return ret; ret = vmw_user_bo_synccpu_grab(vbo, arg->flags); - vmw_user_bo_unref(vbo); + vmw_user_bo_unref(&vbo); if (unlikely(ret != 0)) { if (ret == -ERESTARTSYS || ret == -EBUSY) return -EBUSY; @@ -612,7 +614,6 @@ int vmw_user_bo_lookup(struct drm_file *filp, } *out = to_vmw_bo(gobj); - ttm_bo_get(&(*out)->tbo); return 0; } diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h index 1d433fceed3d..0d496dc9c6af 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h @@ -195,12 +195,19 @@ static inline struct vmw_bo *vmw_bo_reference(struct vmw_bo *buf) return buf; } -static inline void vmw_user_bo_unref(struct vmw_bo *vbo) +static inline struct vmw_bo *vmw_user_bo_ref(struct vmw_bo *vbo) { - if (vbo) { - ttm_bo_put(&vbo->tbo); - drm_gem_object_put(&vbo->tbo.base); - } + drm_gem_object_get(&vbo->tbo.base); + return vbo; +} + +static inline void vmw_user_bo_unref(struct vmw_bo **buf) +{ + struct vmw_bo *tmp_buf = *buf; + + *buf = NULL; + if (tmp_buf) + drm_gem_object_put(&tmp_buf->tbo.base); } static inline struct vmw_bo *to_vmw_bo(struct drm_gem_object *gobj) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c index c0b24d1cacbf..a7c07692262b 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c @@ -432,7 +432,7 @@ static int vmw_cotable_resize(struct vmw_resource *res, size_t new_size) * for the new COTable. Initially pin the buffer object to make sure * we can use tryreserve without failure. */ - ret = vmw_bo_create(dev_priv, &bo_params, &buf); + ret = vmw_gem_object_create(dev_priv, &bo_params, &buf); if (ret) { DRM_ERROR("Failed initializing new cotable MOB.\n"); goto out_done; @@ -502,7 +502,7 @@ static int vmw_cotable_resize(struct vmw_resource *res, size_t new_size) vmw_resource_mob_attach(res); /* Let go of the old mob. */ - vmw_bo_unreference(&old_buf); + vmw_user_bo_unref(&old_buf); res->id = vcotbl->type; ret = dma_resv_reserve_fences(bo->base.resv, 1); @@ -521,7 +521,7 @@ static int vmw_cotable_resize(struct vmw_resource *res, size_t new_size) out_wait: ttm_bo_unpin(bo); ttm_bo_unreserve(bo); - vmw_bo_unreference(&buf); + vmw_user_bo_unref(&buf); out_done: MKS_STAT_TIME_POP(MKSSTAT_KERN_COTABLE_RESIZE); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h index 58bfdf203eca..3cd5090dedfc 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h @@ -853,6 +853,10 @@ static inline bool vmw_resource_mob_attached(const struct vmw_resource *res) /** * GEM related functionality - vmwgfx_gem.c */ +struct vmw_bo_params; +int vmw_gem_object_create(struct vmw_private *vmw, + struct vmw_bo_params *params, + struct vmw_bo **p_vbo); extern int vmw_gem_object_create_with_handle(struct vmw_private *dev_priv, struct drm_file *filp, uint32_t size, diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index 98e0723ca6f5..06b06350f61f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1151,7 +1151,7 @@ static int vmw_translate_mob_ptr(struct vmw_private *dev_priv, SVGAMobId *id, struct vmw_bo **vmw_bo_p) { - struct vmw_bo *vmw_bo; + struct vmw_bo *vmw_bo, *tmp_bo; uint32_t handle = *id; struct vmw_relocation *reloc; int ret; @@ -1164,7 +1164,8 @@ static int vmw_translate_mob_ptr(struct vmw_private *dev_priv, } vmw_bo_placement_set(vmw_bo, VMW_BO_DOMAIN_MOB, VMW_BO_DOMAIN_MOB); ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo); - vmw_user_bo_unref(vmw_bo); + tmp_bo = vmw_bo; + vmw_user_bo_unref(&tmp_bo); if (unlikely(ret != 0)) return ret; @@ -1206,7 +1207,7 @@ static int vmw_translate_guest_ptr(struct vmw_private *dev_priv, SVGAGuestPtr *ptr, struct vmw_bo **vmw_bo_p) { - struct vmw_bo *vmw_bo; + struct vmw_bo *vmw_bo, *tmp_bo; uint32_t handle = ptr->gmrId; struct vmw_relocation *reloc; int ret; @@ -1220,7 +1221,8 @@ static int vmw_translate_guest_ptr(struct vmw_private *dev_priv, vmw_bo_placement_set(vmw_bo, VMW_BO_DOMAIN_GMR | VMW_BO_DOMAIN_VRAM, VMW_BO_DOMAIN_GMR | VMW_BO_DOMAIN_VRAM); ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo); - vmw_user_bo_unref(vmw_bo); + tmp_bo = vmw_bo; + vmw_user_bo_unref(&tmp_bo); if (unlikely(ret != 0)) return ret; diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c index c0da89e16e6f..8b1eb0061610 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c @@ -111,6 +111,20 @@ static const struct drm_gem_object_funcs vmw_gem_object_funcs = { .vm_ops = &vmw_vm_ops, }; +int vmw_gem_object_create(struct vmw_private *vmw, + struct vmw_bo_params *params, + struct vmw_bo **p_vbo) +{ + int ret = vmw_bo_create(vmw, params, p_vbo); + + if (ret != 0) + goto out_no_bo; + + (*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs; +out_no_bo: + return ret; +} + int vmw_gem_object_create_with_handle(struct vmw_private *dev_priv, struct drm_file *filp, uint32_t size, @@ -126,12 +140,10 @@ int vmw_gem_object_create_with_handle(struct vmw_private *dev_priv, .pin = false }; - ret = vmw_bo_create(dev_priv, &params, p_vbo); + ret = vmw_gem_object_create(dev_priv, &params, p_vbo); if (ret != 0) goto out_no_bo; - (*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs; - ret = drm_gem_handle_create(filp, &(*p_vbo)->tbo.base, handle); out_no_bo: return ret; diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c index 1489ad73c103..818b7f109f53 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -1471,8 +1471,8 @@ static int vmw_create_bo_proxy(struct drm_device *dev, /* Reserve and switch the backing mob. */ mutex_lock(&res->dev_priv->cmdbuf_mutex); (void) vmw_resource_reserve(res, false, true); - vmw_bo_unreference(&res->guest_memory_bo); - res->guest_memory_bo = vmw_bo_reference(bo_mob); + vmw_user_bo_unref(&res->guest_memory_bo); + res->guest_memory_bo = vmw_user_bo_ref(bo_mob); res->guest_memory_offset = 0; vmw_resource_unreserve(res, false, false, false, NULL, 0); mutex_unlock(&res->dev_priv->cmdbuf_mutex); @@ -1666,7 +1666,7 @@ static struct drm_framebuffer *vmw_kms_fb_create(struct drm_device *dev, err_out: /* vmw_user_lookup_handle takes one ref so does new_fb */ if (bo) - vmw_user_bo_unref(bo); + vmw_user_bo_unref(&bo); if (surface) vmw_surface_unreference(&surface); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c index fb85f244c3d0..c45b4724e414 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c @@ -451,7 +451,7 @@ int vmw_overlay_ioctl(struct drm_device *dev, void *data, ret = vmw_overlay_update_stream(dev_priv, buf, arg, true); - vmw_user_bo_unref(buf); + vmw_user_bo_unref(&buf); out_unlock: mutex_unlock(&overlay->mutex); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c index 71eeabf001c8..ca300c7427d2 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c @@ -141,7 +141,7 @@ static void vmw_resource_release(struct kref *kref) if (res->coherent) vmw_bo_dirty_release(res->guest_memory_bo); ttm_bo_unreserve(bo); - vmw_bo_unreference(&res->guest_memory_bo); + vmw_user_bo_unref(&res->guest_memory_bo); } if (likely(res->hw_destroy != NULL)) { @@ -338,7 +338,7 @@ static int vmw_resource_buf_alloc(struct vmw_resource *res, return 0; } - ret = vmw_bo_create(res->dev_priv, &bo_params, &gbo); + ret = vmw_gem_object_create(res->dev_priv, &bo_params, &gbo); if (unlikely(ret != 0)) goto out_no_bo; @@ -457,11 +457,11 @@ void vmw_resource_unreserve(struct vmw_resource *res, vmw_resource_mob_detach(res); if (res->coherent) vmw_bo_dirty_release(res->guest_memory_bo); - vmw_bo_unreference(&res->guest_memory_bo); + vmw_user_bo_unref(&res->guest_memory_bo); } if (new_guest_memory_bo) { - res->guest_memory_bo = vmw_bo_reference(new_guest_memory_bo); + res->guest_memory_bo = vmw_user_bo_ref(new_guest_memory_bo); /* * The validation code should already have added a @@ -551,7 +551,7 @@ vmw_resource_check_buffer(struct ww_acquire_ctx *ticket, ttm_bo_put(val_buf->bo); val_buf->bo = NULL; if (guest_memory_dirty) - vmw_bo_unreference(&res->guest_memory_bo); + vmw_user_bo_unref(&res->guest_memory_bo); return ret; } @@ -727,7 +727,7 @@ int vmw_resource_validate(struct vmw_resource *res, bool intr, goto out_no_validate; else if (!res->func->needs_guest_memory && res->guest_memory_bo) { WARN_ON_ONCE(vmw_resource_mob_attached(res)); - vmw_bo_unreference(&res->guest_memory_bo); + vmw_user_bo_unref(&res->guest_memory_bo); } return 0; diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c index 1e81ff2422cf..a01ca3226d0a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c @@ -180,7 +180,7 @@ static int vmw_gb_shader_init(struct vmw_private *dev_priv, res->guest_memory_size = size; if (byte_code) { - res->guest_memory_bo = vmw_bo_reference(byte_code); + res->guest_memory_bo = vmw_user_bo_ref(byte_code); res->guest_memory_offset = offset; } shader->size = size; @@ -809,7 +809,7 @@ static int vmw_shader_define(struct drm_device *dev, struct drm_file *file_priv, shader_type, num_input_sig, num_output_sig, tfile, shader_handle); out_bad_arg: - vmw_user_bo_unref(buffer); + vmw_user_bo_unref(&buffer); return ret; } diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 5db403ee8261..3829be282ff0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -686,9 +686,6 @@ static void vmw_user_surface_base_release(struct ttm_base_object **p_base) container_of(base, struct vmw_user_surface, prime.base); struct vmw_resource *res = &user_srf->srf.res; - if (res->guest_memory_bo) - drm_gem_object_put(&res->guest_memory_bo->tbo.base); - *p_base = NULL; vmw_resource_unreference(&res); } @@ -855,23 +852,21 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data, * expect a backup buffer to be present. */ if (dev_priv->has_mob && req->shareable) { - uint32_t backup_handle; - - ret = vmw_gem_object_create_with_handle(dev_priv, - file_priv, - res->guest_memory_size, - &backup_handle, - &res->guest_memory_bo); + struct vmw_bo_params params = { + .domain = VMW_BO_DOMAIN_SYS, + .busy_domain = VMW_BO_DOMAIN_SYS, + .bo_type = ttm_bo_type_device, + .size = res->guest_memory_size, + .pin = false + }; + + ret = vmw_gem_object_create(dev_priv, + &params, + &res->guest_memory_bo); if (unlikely(ret != 0)) { vmw_resource_unreference(&res); goto out_unlock; } - vmw_bo_reference(res->guest_memory_bo); - /* - * We don't expose the handle to the userspace and surface - * already holds a gem reference - */ - drm_gem_handle_delete(file_priv, backup_handle); } tmp = vmw_resource_reference(&srf->res); @@ -1512,7 +1507,7 @@ vmw_gb_surface_define_internal(struct drm_device *dev, if (ret == 0) { if (res->guest_memory_bo->tbo.base.size < res->guest_memory_size) { VMW_DEBUG_USER("Surface backup buffer too small.\n"); - vmw_bo_unreference(&res->guest_memory_bo); + vmw_user_bo_unref(&res->guest_memory_bo); ret = -EINVAL; goto out_unlock; } else { @@ -1526,8 +1521,6 @@ vmw_gb_surface_define_internal(struct drm_device *dev, res->guest_memory_size, &backup_handle, &res->guest_memory_bo); - if (ret == 0) - vmw_bo_reference(res->guest_memory_bo); } if (unlikely(ret != 0)) { -- 2.39.2

1 year, 1 month

4
3
0 0

[PATCH] ACPI: APEI: set memory failure flags as MF_ACTION_REQUIRED on action required events

by Shuai Xue

There are two major types of uncorrected error (UC) : - Action Required: The error is detected and the processor already consumes the memory. OS requires to take action (for example, offline failure page/kill failure thread) to recover this uncorrectable error. - Action Optional: The error is detected out of processor execution context. Some data in the memory are corrupted. But the data have not been consumed. OS is optional to take action to recover this uncorrectable error. For X86 platforms, we can easily distinguish between these two types based on the MCA Bank. While for arm64 platform, the memory failure flags for all UCs which severity are GHES_SEV_RECOVERABLE are set as 0, a.k.a, Action Optional now. If UC is detected by a background scrubber, it is obviously an Action Optional error. For other errors, we should conservatively regard them as Action Required. cper_sec_mem_err::error_type identifies the type of error that occurred if CPER_MEM_VALID_ERROR_TYPE is set. So, set memory failure flags as 0 for Scrub Uncorrected Error (type 14). Otherwise, set memory failure flags as MF_ACTION_REQUIRED. Signed-off-by: Shuai Xue <xueshuai(a)linux.alibaba.com> --- drivers/acpi/apei/ghes.c | 10 ++++++++-- include/linux/cper.h | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 80ad530583c9..6c03059cbfc6 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -474,8 +474,14 @@ static bool ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, if (sec_sev == GHES_SEV_CORRECTED && (gdata->flags & CPER_SEC_ERROR_THRESHOLD_EXCEEDED)) flags = MF_SOFT_OFFLINE; - if (sev == GHES_SEV_RECOVERABLE && sec_sev == GHES_SEV_RECOVERABLE) - flags = 0; + if (sev == GHES_SEV_RECOVERABLE && sec_sev == GHES_SEV_RECOVERABLE) { + if (mem_err->validation_bits & CPER_MEM_VALID_ERROR_TYPE) + flags = mem_err->error_type == CPER_MEM_SCRUB_UC ? + 0 : + MF_ACTION_REQUIRED; + else + flags = MF_ACTION_REQUIRED; + } if (flags != -1) return ghes_do_memory_failure(mem_err->physical_addr, flags); diff --git a/include/linux/cper.h b/include/linux/cper.h index eacb7dd7b3af..b77ab7636614 100644 --- a/include/linux/cper.h +++ b/include/linux/cper.h @@ -235,6 +235,9 @@ enum { #define CPER_MEM_VALID_BANK_ADDRESS 0x100000 #define CPER_MEM_VALID_CHIP_ID 0x200000 +#define CPER_MEM_SCRUB_CE 13 +#define CPER_MEM_SCRUB_UC 14 + #define CPER_MEM_EXT_ROW_MASK 0x3 #define CPER_MEM_EXT_ROW_SHIFT 16 -- 2.20.1.9.gb50a0d7

1 year, 1 month

9
45
0 0

[RFT 1/2] RISC-V: handle missing "no-map" properties for OpenSBI's PMP protected regions

by Conor Dooley

Add an erratum for versions [v0.8 to v1.3) of OpenSBI which fail to add the "no-map" property to the reserved memory nodes for the regions it has protected using PMPs. Our existing fix sweeping hibernation under the carpet by marking it NONPORTABLE is insufficient as there are other ways to generate accesses to these reserved memory regions, as Petr discovered [1] while testing crash kernels & kdump. Intercede during the boot process when the afflicted versions of OpenSBI are present & set the "no-map" property in all "mmode_resv" nodes before the kernel does its reserved memory region initialisation. Reported-by: Song Shuai <suagrfillet(a)gmail.com> Link: https://lore.kernel.org/all/CAAYs2=gQvkhTeioMmqRDVGjdtNF_vhB+vm_1dHJxPNi75Y… Reported-by: JeeHeng Sia <jeeheng.sia(a)starfivetech.com> Link: https://groups.google.com/a/groups.riscv.org/g/sw-dev/c/ITXwaKfA6z8 Reported-by: Petr Tesarik <petrtesarik(a)huaweicloud.com> Closes: https://lore.kernel.org/linux-riscv/76ff0f51-d6c1-580d-f943-061e93073306@hu… [1] CC: stable(a)vger.kernel.org Signed-off-by: Conor Dooley <conor.dooley(a)microchip.com> --- arch/riscv/include/asm/sbi.h | 5 +++++ arch/riscv/kernel/sbi.c | 42 +++++++++++++++++++++++++++++++++++- arch/riscv/mm/init.c | 3 +++ 3 files changed, 49 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 5b4a1bf5f439..5360f3476278 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -252,6 +252,9 @@ enum sbi_pmu_ctr_type { #define SBI_ERR_ALREADY_STARTED -7 #define SBI_ERR_ALREADY_STOPPED -8 +/* SBI implementation IDs */ +#define SBI_IMP_OPENSBI 1 + extern unsigned long sbi_spec_version; struct sbiret { long error; @@ -259,6 +262,8 @@ struct sbiret { }; void sbi_init(void); +void sbi_apply_reserved_mem_erratum(void *dtb_va); + struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, unsigned long arg1, unsigned long arg2, unsigned long arg3, unsigned long arg4, diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index c672c8ba9a2a..aeb27263fa53 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -5,8 +5,10 @@ * Copyright (c) 2020 Western Digital Corporation or its affiliates. */ +#include <linux/acpi.h> #include <linux/bits.h> #include <linux/init.h> +#include <linux/libfdt.h> #include <linux/pm.h> #include <linux/reboot.h> #include <asm/sbi.h> @@ -583,6 +585,40 @@ long sbi_get_mimpid(void) } EXPORT_SYMBOL_GPL(sbi_get_mimpid); +static long sbi_firmware_id; +static long sbi_firmware_version; + +/* + * For devicetrees patched by OpenSBI a "mmode_resv" node is added to cover + * the region OpenSBI has protected by means of a PMP. Some versions of OpenSBI, + * [v0.8 to v1.3), omitted the "no-map" property, but this trips up hibernation + * among other things. + */ +void __init sbi_apply_reserved_mem_erratum(void *dtb_pa) +{ + int child, reserved_mem; + + if (sbi_firmware_id != SBI_IMP_OPENSBI) + return; + + if (!acpi_disabled) + return; + + if (sbi_firmware_version >= 0x10003 || sbi_firmware_version < 0x8) + return; + + reserved_mem = fdt_path_offset((void *)dtb_pa, "/reserved-memory"); + if (reserved_mem < 0) + return; + + fdt_for_each_subnode(child, (void *)dtb_pa, reserved_mem) { + const char *name = fdt_get_name((void *)dtb_pa, child, NULL); + + if (!strncmp(name, "mmode_resv", 10)) + fdt_setprop((void *)dtb_pa, child, "no-map", NULL, 0); + } +}; + void __init sbi_init(void) { int ret; @@ -596,8 +632,12 @@ void __init sbi_init(void) sbi_major_version(), sbi_minor_version()); if (!sbi_spec_is_0_1()) { + sbi_firmware_id = sbi_get_firmware_id(); + sbi_firmware_version = sbi_get_firmware_version(); + pr_info("SBI implementation ID=0x%lx Version=0x%lx\n", - sbi_get_firmware_id(), sbi_get_firmware_version()); + sbi_firmware_id, sbi_firmware_version); + if (sbi_probe_extension(SBI_EXT_TIME)) { __sbi_set_timer = __sbi_set_timer_v02; pr_info("SBI TIME extension detected\n"); diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 70fb31960b63..cb16bfdeacdb 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -29,6 +29,7 @@ #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/soc.h> +#include <asm/sbi.h> #include <asm/io.h> #include <asm/ptdump.h> #include <asm/numa.h> @@ -253,6 +254,8 @@ static void __init setup_bootmem(void) * in the device tree, otherwise the allocation could end up in a * reserved region. */ + + sbi_apply_reserved_mem_erratum(dtb_early_va); early_init_fdt_scan_reserved_mem(); /* -- 2.40.1

1 year, 1 month

8
19
0 0

FAILED: patch "[PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-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(a)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-5.15.y git checkout FETCH_HEAD git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080733-wife-elope-de1b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S") 228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller") 9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()") 76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S") fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set") 34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()") 4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S") 41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32") 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller") 0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller") 40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS") c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") 7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()") 7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32") c545b9f040f3 ("powerpc/inst: Define ppc_inst_t") aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros") 7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001 From: Naveen N Rao <naveen(a)kernel.org> Date: Wed, 21 Jun 2023 10:43:49 +0530 Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable(a)vger.kernel.org Signed-off-by: Naveen N Rao <naveen(a)kernel.org> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S index ffb1db386849..1f7d86de1538 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -33,6 +33,9 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) @@ -42,7 +45,7 @@ #ifdef CONFIG_PPC64 /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE(r1) + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 @@ -77,6 +80,8 @@ mflr r7 /* Save it as pt_regs->nip */ PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -142,7 +147,7 @@ #endif /* Pop our stack frame */ - addi r1, r1, SWITCH_FRAME_SIZE + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE #ifdef CONFIG_LIVEPATCH_64 /* Based on the cmpd above, if the NIP was altered handle livepatch */

1 year, 1 month

3
3
0 0

FAILED: patch "[PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-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(a)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-5.10.y git checkout FETCH_HEAD git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080735-masculine-twister-ba16@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S") 228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller") 9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()") 76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S") fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set") 34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()") 4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S") 41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32") 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller") 0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller") 40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS") c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") 7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()") 7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32") c545b9f040f3 ("powerpc/inst: Define ppc_inst_t") aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros") 7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001 From: Naveen N Rao <naveen(a)kernel.org> Date: Wed, 21 Jun 2023 10:43:49 +0530 Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable(a)vger.kernel.org Signed-off-by: Naveen N Rao <naveen(a)kernel.org> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S index ffb1db386849..1f7d86de1538 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -33,6 +33,9 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) @@ -42,7 +45,7 @@ #ifdef CONFIG_PPC64 /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE(r1) + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 @@ -77,6 +80,8 @@ mflr r7 /* Save it as pt_regs->nip */ PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -142,7 +147,7 @@ #endif /* Pop our stack frame */ - addi r1, r1, SWITCH_FRAME_SIZE + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE #ifdef CONFIG_LIVEPATCH_64 /* Based on the cmpd above, if the NIP was altered handle livepatch */

1 year, 1 month

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FAILED: patch "[PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-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(a)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-5.4.y git checkout FETCH_HEAD git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080737-guileless-magazine-d8dc@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S") 228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller") 9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()") 76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S") fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set") 34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()") 4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S") 41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32") 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller") 0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller") 40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS") c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") 7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()") 7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32") c545b9f040f3 ("powerpc/inst: Define ppc_inst_t") aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros") 7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001 From: Naveen N Rao <naveen(a)kernel.org> Date: Wed, 21 Jun 2023 10:43:49 +0530 Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable(a)vger.kernel.org Signed-off-by: Naveen N Rao <naveen(a)kernel.org> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S index ffb1db386849..1f7d86de1538 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -33,6 +33,9 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) @@ -42,7 +45,7 @@ #ifdef CONFIG_PPC64 /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE(r1) + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 @@ -77,6 +80,8 @@ mflr r7 /* Save it as pt_regs->nip */ PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -142,7 +147,7 @@ #endif /* Pop our stack frame */ - addi r1, r1, SWITCH_FRAME_SIZE + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE #ifdef CONFIG_LIVEPATCH_64 /* Based on the cmpd above, if the NIP was altered handle livepatch */

1 year, 1 month

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FAILED: patch "[PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-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(a)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-4.19.y git checkout FETCH_HEAD git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080739-bonehead-overexert-ce34@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S") 228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller") 9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()") 76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S") fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set") 34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()") 4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S") 41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32") 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller") 0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller") 40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS") c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") 7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()") 7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32") c545b9f040f3 ("powerpc/inst: Define ppc_inst_t") aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros") 7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001 From: Naveen N Rao <naveen(a)kernel.org> Date: Wed, 21 Jun 2023 10:43:49 +0530 Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable(a)vger.kernel.org Signed-off-by: Naveen N Rao <naveen(a)kernel.org> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S index ffb1db386849..1f7d86de1538 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -33,6 +33,9 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) @@ -42,7 +45,7 @@ #ifdef CONFIG_PPC64 /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE(r1) + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 @@ -77,6 +80,8 @@ mflr r7 /* Save it as pt_regs->nip */ PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -142,7 +147,7 @@ #endif /* Pop our stack frame */ - addi r1, r1, SWITCH_FRAME_SIZE + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE #ifdef CONFIG_LIVEPATCH_64 /* Based on the cmpd above, if the NIP was altered handle livepatch */

1 year, 1 month

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FAILED: patch "[PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-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(a)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-4.14.y git checkout FETCH_HEAD git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080741-polka-twice-b0df@gregkh' --subject-prefix 'PATCH 4.14.y' HEAD^.. Possible dependencies: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S") 228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller") 9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()") 76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S") fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set") 34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()") 4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S") 41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32") 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller") 0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller") 40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS") c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS") 7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()") 7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32") c545b9f040f3 ("powerpc/inst: Define ppc_inst_t") aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros") 7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001 From: Naveen N Rao <naveen(a)kernel.org> Date: Wed, 21 Jun 2023 10:43:49 +0530 Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable(a)vger.kernel.org Signed-off-by: Naveen N Rao <naveen(a)kernel.org> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S index ffb1db386849..1f7d86de1538 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -33,6 +33,9 @@ * and then arrange for the ftrace function to be called. */ .macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + /* Create our stack frame + pt_regs */ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) @@ -42,7 +45,7 @@ #ifdef CONFIG_PPC64 /* Save the original return address in A's stack frame */ - std r0, LRSAVE+SWITCH_FRAME_SIZE(r1) + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) /* Ok to continue? */ lbz r3, PACA_FTRACE_ENABLED(r13) cmpdi r3, 0 @@ -77,6 +80,8 @@ mflr r7 /* Save it as pt_regs->nip */ PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) /* Save the read LR in pt_regs->link */ PPC_STL r0, _LINK(r1) @@ -142,7 +147,7 @@ #endif /* Pop our stack frame */ - addi r1, r1, SWITCH_FRAME_SIZE + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE #ifdef CONFIG_LIVEPATCH_64 /* Based on the cmpd above, if the NIP was altered handle livepatch */

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Linux-stable-mirror October 2023