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[PATCH v2 01/13] KVM: SVM: Switch svm_copy_lbrs() to a macro

by Yosry Ahmed

In preparation for using svm_copy_lbrs() with 'struct vmcb_save_area' without a containing 'struct vmcb', and later even 'struct vmcb_save_area_cached', make it a macro. Pull the call to vmcb_mark_dirty() out to the callers. Macros are generally not preferred compared to functions, mainly due to type-safety. However, in this case it seems like having a simple macro copying a few fields is better than copy-pasting the same 5 lines of code in different places. On the bright side, pulling vmcb_mark_dirty() calls to the callers makes it clear that in one case, vmcb_mark_dirty() was being called on VMCB12. It is not architecturally defined for the CPU to clear arbitrary clean bits, and it is not needed, so drop that one call. Technically fixes the non-architectural behavior of setting the dirty bit on VMCB12. Fixes: d20c796ca370 ("KVM: x86: nSVM: implement nested LBR virtualization") Cc: stable(a)vger.kernel.org Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> --- arch/x86/kvm/svm/nested.c | 16 ++++++++++------ arch/x86/kvm/svm/svm.c | 11 ----------- arch/x86/kvm/svm/svm.h | 10 +++++++++- 3 files changed, 19 insertions(+), 18 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index da6e80b3ac353..a37bd5c1f36fa 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -675,10 +675,12 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 * Reserved bits of DEBUGCTL are ignored. Be consistent with * svm_set_msr's definition of reserved bits. */ - svm_copy_lbrs(vmcb02, vmcb12); + svm_copy_lbrs(&vmcb02->save, &vmcb12->save); + vmcb_mark_dirty(vmcb02, VMCB_LBR); vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS; } else { - svm_copy_lbrs(vmcb02, vmcb01); + svm_copy_lbrs(&vmcb02->save, &vmcb01->save); + vmcb_mark_dirty(vmcb02, VMCB_LBR); } svm_update_lbrv(&svm->vcpu); } @@ -1184,10 +1186,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm) kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && - (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) - svm_copy_lbrs(vmcb12, vmcb02); - else - svm_copy_lbrs(vmcb01, vmcb02); + (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { + svm_copy_lbrs(&vmcb12->save, &vmcb02->save); + } else { + svm_copy_lbrs(&vmcb01->save, &vmcb02->save); + vmcb_mark_dirty(vmcb01, VMCB_LBR); + } svm_update_lbrv(vcpu); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 10c21e4c5406f..711276e8ee84f 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -795,17 +795,6 @@ static void svm_recalc_msr_intercepts(struct kvm_vcpu *vcpu) */ } -void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb) -{ - to_vmcb->save.dbgctl = from_vmcb->save.dbgctl; - to_vmcb->save.br_from = from_vmcb->save.br_from; - to_vmcb->save.br_to = from_vmcb->save.br_to; - to_vmcb->save.last_excp_from = from_vmcb->save.last_excp_from; - to_vmcb->save.last_excp_to = from_vmcb->save.last_excp_to; - - vmcb_mark_dirty(to_vmcb, VMCB_LBR); -} - static void __svm_enable_lbrv(struct kvm_vcpu *vcpu) { to_svm(vcpu)->vmcb->control.virt_ext |= LBR_CTL_ENABLE_MASK; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index c856d8e0f95e7..f6fb70ddf7272 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -687,8 +687,16 @@ static inline void *svm_vcpu_alloc_msrpm(void) return svm_alloc_permissions_map(MSRPM_SIZE, GFP_KERNEL_ACCOUNT); } +#define svm_copy_lbrs(to, from) \ +({ \ + (to)->dbgctl = (from)->dbgctl; \ + (to)->br_from = (from)->br_from; \ + (to)->br_to = (from)->br_to; \ + (to)->last_excp_from = (from)->last_excp_from; \ + (to)->last_excp_to = (from)->last_excp_to; \ +}) + void svm_vcpu_free_msrpm(void *msrpm); -void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb); void svm_enable_lbrv(struct kvm_vcpu *vcpu); void svm_update_lbrv(struct kvm_vcpu *vcpu); -- 2.51.2.1041.gc1ab5b90ca-goog

3 weeks, 2 days

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by lists.linaro.org Server Support

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by lists.linaro.org Server Support

3 weeks, 2 days

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[PATCH AUTOSEL 6.17-6.12] drm/amdgpu: fix gpu page fault after hibernation on PF passthrough

by Sasha Levin

From: Samuel Zhang <guoqing.zhang(a)amd.com> [ Upstream commit eb6e7f520d6efa4d4ebf1671455abe4a681f7a05 ] On PF passthrough environment, after hibernate and then resume, coralgemm will cause gpu page fault. Mode1 reset happens during hibernate, but partition mode is not restored on resume, register mmCP_HYP_XCP_CTL and mmCP_PSP_XCP_CTL is not right after resume. When CP access the MQD BO, wrong stride size is used, this will cause out of bound access on the MQD BO, resulting page fault. The fix is to ensure gfx_v9_4_3_switch_compute_partition() is called when resume from a hibernation. KFD resume is called separately during a reset recovery or resume from suspend sequence. Hence it's not required to be called as part of partition switch. Signed-off-by: Samuel Zhang <guoqing.zhang(a)amd.com> Reviewed-by: Lijo Lazar <lijo.lazar(a)amd.com> Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com> (cherry picked from commit 5d1b32cfe4a676fe552416cb5ae847b215463a1a) Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: Based on my comprehensive analysis using semantic code analysis tools and repository examination, here's my assessment: ## **BACKPORT DECISION: YES** ### Analysis Process and Findings: #### 1. **Semantic Analysis Tools Used:** - **mcp__semcode__find_function**: Located `aqua_vanjaram_switch_partition_mode`, `gfx_v9_4_3_cp_resume`, and `amdgpu_xcp_restore_partition_mode` - **mcp__semcode__find_callers**: Traced call graph showing `gfx_v9_4_3_cp_resume` is called during resume via `gfx_v9_4_3_hw_init` - **mcp__semcode__find_callchain**: Confirmed the resume path and analyzed impact scope - **mcp__semcode__find_type**: Examined `struct amdgpu_device` to verify `in_suspend` flag management - **WebSearch**: Found mailing list discussions showing multiple patch iterations (v2, v3, v4) - **Repository analysis**: Traced historical context and related commits #### 2. **Impact Analysis:** **Severity: HIGH** - This fixes GPU page faults that crash user workloads - **Hardware affected**: Aqua Vanjaram/MI300 series datacenter GPUs (gfx_v9_4_3, IP versions 9.4.4 and 9.5.0) - **Configuration**: PF passthrough environments (SR-IOV virtualization) - **Trigger**: User-space reachable via hibernation cycle + workload execution - **Root cause**: Out-of-bounds memory access on MQD (Memory Queue Descriptor) buffer object due to wrong CP register values (CP_HYP_XCP_CTL) #### 3. **Code Changes Analysis:** **Two minimal, targeted changes:** **Change 1** (drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c:410-411): ```c -if (adev->kfd.init_complete && !amdgpu_in_reset(adev)) +if (adev->kfd.init_complete && !amdgpu_in_reset(adev) && !adev->in_suspend) flags |= AMDGPU_XCP_OPS_KFD; ``` - Prevents KFD operations during suspend/hibernation - KFD resume is handled separately in the resume sequence **Change 2** (drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c:2295-2298): ```c +if (adev->in_suspend) + amdgpu_xcp_restore_partition_mode(adev->xcp_mgr); +else if (amdgpu_xcp_query_partition_mode(...) == AMDGPU_UNKNOWN_COMPUTE_PARTITION_MODE) ``` - Adds hibernation resume handling to restore partition mode - Uses existing `amdgpu_xcp_restore_partition_mode()` function (added in c45e38f21754b, Sept 2023) - Ensures CP registers get correct values on resume #### 4. **Scope and Dependencies:** - **Contained fix**: Only 3 lines changed across 2 files - **Existing infrastructure**: Depends on `amdgpu_xcp_restore_partition_mode()` which has been in the kernel since Sept 2023 - **Low coupling**: Changes are isolated to resume path, don't affect normal operation - **Call graph impact**: Minimal - only affects hibernation resume codepath #### 5. **Stable Tree Compliance:** ✅ **Bug fix**: Yes - fixes GPU page faults ✅ **Small and contained**: 3-line change ✅ **No new features**: Uses existing restore function ✅ **No architectural changes**: Follows pattern from c45e38f21754b ❌ **Stable tags**: No "Fixes:" or "Cc: stable@" tags present However, the absence of stable tags appears to be an oversight given the severity. #### 6. **Risk Assessment:** **Low regression risk:** - Only affects specific hardware (Aqua Vanjaram GPUs) - Only impacts PF passthrough configuration - Only touches hibernation resume path - Multiple patch iterations suggest thorough testing - Builds on proven pattern from 2023 reset handling #### 7. **Historical Context:** - Part of ongoing partition mode fixes (multiple related commits in 2024-2025) - Web search revealed extensive mailing list discussion - Multiple patch versions (v2, v3, v4) indicate careful upstream review - Targeted for drm-next-6.19 ### Conclusion: This commit **SHOULD be backported** because it: 1. Fixes a serious user-visible bug (GPU crashes from page faults) 2. Has minimal code changes with low regression risk 3. Affects critical datacenter hardware (MI300 series) 4. Is well-tested with multiple upstream review cycles 5. Follows established architectural patterns 6. Is confined to a specific use case, limiting blast radius The fix is essential for users running AMD MI300 GPUs in virtualized environments with hibernation support. drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c | 3 ++- drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c | 4 +++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c b/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c index 811124ff88a88..f9e2edf5260bc 100644 --- a/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c +++ b/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c @@ -407,7 +407,8 @@ static int aqua_vanjaram_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, return -EINVAL; } - if (adev->kfd.init_complete && !amdgpu_in_reset(adev)) + if (adev->kfd.init_complete && !amdgpu_in_reset(adev) && + !adev->in_suspend) flags |= AMDGPU_XCP_OPS_KFD; if (flags & AMDGPU_XCP_OPS_KFD) { diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c index 51babf5c78c86..02c69ffd05837 100644 --- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c @@ -2292,7 +2292,9 @@ static int gfx_v9_4_3_cp_resume(struct amdgpu_device *adev) r = amdgpu_xcp_init(adev->xcp_mgr, num_xcp, mode); } else { - if (amdgpu_xcp_query_partition_mode(adev->xcp_mgr, + if (adev->in_suspend) + amdgpu_xcp_restore_partition_mode(adev->xcp_mgr); + else if (amdgpu_xcp_query_partition_mode(adev->xcp_mgr, AMDGPU_XCP_FL_NONE) == AMDGPU_UNKNOWN_COMPUTE_PARTITION_MODE) r = amdgpu_xcp_switch_partition_mode( -- 2.51.0

3 weeks, 2 days

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[PATCH 4/6] KVM: SVM: Switch svm_copy_lbrs() to a macro

by Yosry Ahmed

In preparation for using svm_copy_lbrs() with 'struct vmcb_save_area' without a containing 'struct vmcb', and later even 'struct vmcb_save_area_cached', make it a macro. Pull the call to vmcb_mark_dirty() out to the callers. Macros are generally not preferred compared to functions, mainly due to type-safety. However, in this case it seems like having a simple macro copying a few fields is better than copy-pasting the same 5 lines of code in different places. On the bright side, pulling vmcb_mark_dirty() calls to the callers makes it clear that in one case, vmcb_mark_dirty() was being called on VMCB12. It is not architecturally defined for the CPU to clear arbitrary clean bits, and it is not needed, so drop that one call. Technically fixes the non-architectural behavior of setting the dirty bit on VMCB12. Fixes: d20c796ca370 ("KVM: x86: nSVM: implement nested LBR virtualization") Cc: stable(a)vger.kernel.org Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> --- arch/x86/kvm/svm/nested.c | 16 ++++++++++------ arch/x86/kvm/svm/svm.c | 11 ----------- arch/x86/kvm/svm/svm.h | 10 +++++++++- 3 files changed, 19 insertions(+), 18 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index c81005b245222..e7861392f2fcd 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -676,10 +676,12 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 * Reserved bits of DEBUGCTL are ignored. Be consistent with * svm_set_msr's definition of reserved bits. */ - svm_copy_lbrs(vmcb02, vmcb12); + svm_copy_lbrs(&vmcb02->save, &vmcb12->save); + vmcb_mark_dirty(vmcb02, VMCB_LBR); vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS; } else { - svm_copy_lbrs(vmcb02, vmcb01); + svm_copy_lbrs(&vmcb02->save, &vmcb01->save); + vmcb_mark_dirty(vmcb02, VMCB_LBR); } svm_update_lbrv(&svm->vcpu); } @@ -1186,10 +1188,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm) kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && - (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) - svm_copy_lbrs(vmcb12, vmcb02); - else - svm_copy_lbrs(vmcb01, vmcb02); + (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { + svm_copy_lbrs(&vmcb12->save, &vmcb02->save); + } else { + svm_copy_lbrs(&vmcb01->save, &vmcb02->save); + vmcb_mark_dirty(vmcb01, VMCB_LBR); + } svm_update_lbrv(vcpu); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index fc42bcdbb5200..9eb112f0e61f0 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -795,17 +795,6 @@ static void svm_recalc_msr_intercepts(struct kvm_vcpu *vcpu) */ } -void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb) -{ - to_vmcb->save.dbgctl = from_vmcb->save.dbgctl; - to_vmcb->save.br_from = from_vmcb->save.br_from; - to_vmcb->save.br_to = from_vmcb->save.br_to; - to_vmcb->save.last_excp_from = from_vmcb->save.last_excp_from; - to_vmcb->save.last_excp_to = from_vmcb->save.last_excp_to; - - vmcb_mark_dirty(to_vmcb, VMCB_LBR); -} - static void __svm_enable_lbrv(struct kvm_vcpu *vcpu) { to_svm(vcpu)->vmcb->control.virt_ext |= LBR_CTL_ENABLE_MASK; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index c2acaa49ee1c5..e510c8183bd87 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -687,8 +687,16 @@ static inline void *svm_vcpu_alloc_msrpm(void) return svm_alloc_permissions_map(MSRPM_SIZE, GFP_KERNEL_ACCOUNT); } +#define svm_copy_lbrs(to, from) \ +({ \ + (to)->dbgctl = (from)->dbgctl; \ + (to)->br_from = (from)->br_from; \ + (to)->br_to = (from)->br_to; \ + (to)->last_excp_from = (from)->last_excp_from; \ + (to)->last_excp_to = (from)->last_excp_to; \ +}) + void svm_vcpu_free_msrpm(void *msrpm); -void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb); void svm_enable_lbrv(struct kvm_vcpu *vcpu); void svm_update_lbrv(struct kvm_vcpu *vcpu); -- 2.51.2.1041.gc1ab5b90ca-goog

3 weeks, 2 days

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Gestiona el desempeño con objetivos claros y medibles

by Luis Ramírez

Gestiona el desempeño con Vorecol body { margin: 0; padding: 0; font-family: Arial, Helvetica, sans-serif; font-size: 14px; color: #333; background-color: #ffffff; } table { border-spacing: 0; width: 100%; max-width: 600px; margin: auto; } td { padding: 12px 20px; } a { color: #1a73e8; text-decoration: none; } .footer { font-size: 12px; color: #888888; text-align: center; } Mejora la gestión del desempeño y talento con Vorecol Performance Management. Hola , Gestionar el desempeño de tu equipo puede ser más sencillo y efectivo con las herramientas adecuadas. Sin un buen sistema, es difícil identificar, desarrollar y retener a los mejores colaboradores. El módulo de Performance Management de Vorecol te ofrece una solución completa para medir y potenciar el talento en tu organización. Con este módulo puedes: Evaluar el desempeño y potencial de tus colaboradores con la matriz Nine Box para tomar mejores decisiones. Establecer y seguir objetivos claros usando la metodología SMART, alineados con las prioridades de tu empresa. Ajustar el sistema según lo que necesites, desde manejar los periodos hasta recibir notificaciones, todo fácil de usar. Además, contarás con soporte técnico y capacitación especializada para resolver cualquier duda y aprovechar al máximo la herramienta. Aprovecha el Buen Fin del 1 al 22 de noviembre con hasta 15% de descuento y descubre cómo mejorar la gestión del desempeño en tu equipo. Si quieres conocer más, responde este correo o contáctame directamente. Saludos, -------------- Atte.: Luis Ramírez Ciudad de México: (55) 5018 0565 WhatsApp: +52 33 1607 2089 Si no deseas recibir más correos, haz clic aquí para darte de baja. Para remover su dirección de esta lista haga <a href="https://s1.arrobamail.com/unsuscribe.php?id=yiwtsrewiswqwqseup">click aquí</a>

3 weeks, 2 days

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Re: Patch "net: ionic: add dma_wmb() before ringing TX doorbell" has been added to the 6.12-stable tree

by Brett Creeley

On 11/8/2025 9:26 AM, Sasha Levin wrote: > Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding. > > > This is a note to let you know that I've just added the patch titled > > net: ionic: add dma_wmb() before ringing TX doorbell > > to the 6.12-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… > > The filename of the patch is: > net-ionic-add-dma_wmb-before-ringing-tx-doorbell.patch > and it can be found in the queue-6.12 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. > > > > commit 05587f91cc2e8b071605aeef6442d2acf6e627c9 > Author: Mohammad Heib <mheib(a)redhat.com> > Date: Fri Oct 31 17:52:02 2025 +0200 > > net: ionic: add dma_wmb() before ringing TX doorbell > > [ Upstream commit d261f5b09c28850dc63ca1d3018596f829f402d5 ] > > The TX path currently writes descriptors and then immediately writes to > the MMIO doorbell register to notify the NIC. On weakly ordered > architectures, descriptor writes may still be pending in CPU or DMA > write buffers when the doorbell is issued, leading to the device > fetching stale or incomplete descriptors. > > Add a dma_wmb() in ionic_txq_post() to ensure all descriptor writes are > visible to the device before the doorbell MMIO write. > > Fixes: 0f3154e6bcb3 ("ionic: Add Tx and Rx handling") > Signed-off-by: Mohammad Heib <mheib(a)redhat.com> > Link: https://patch.msgid.link/20251031155203.203031-1-mheib@redhat.com > Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> > Signed-off-by: Sasha Levin <sashal(a)kernel.org> > > diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c > index 0f5758c273c22..3a094d3ea6f4f 100644 > --- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c > +++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c > @@ -29,6 +29,10 @@ static void ionic_tx_clean(struct ionic_queue *q, > > static inline void ionic_txq_post(struct ionic_queue *q, bool ring_dbell) > { > + /* Ensure TX descriptor writes reach memory before NIC reads them. > + * Prevents device from fetching stale descriptors. > + */ > + dma_wmb(); > ionic_q_post(q, ring_dbell); > } > I posted on the original patch, but I will post here as well. Apologies for the late and duplicate response, but it's not clear to me why this is necessary. In other vendors the "doorbell record" (dbr) is writing another location in system memory, not an mmio write. These cases do use a dma_wmb(). Why isn't the writeq() sufficient in our case? According to Documentation/memory-barriers.txt it seems like writeq() should be sufficient. Thanks, Brett

3 weeks, 2 days

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PROBLEM: boot hang on Indy R4400SC (regression)

by Nick Bowler

Hi, After a recent 6.1.y stable kernel update, my Indy (mips64 R4400SC) now just stops booting early, just before when I would normally see the kernel messages about mounting the root filesystem. There are no further messages of any kind, and the boot process does not appear to ever complete. However, the kernel is not fully crashed, as it does respond to sysrq commands from the keyboard (and I do get output on the console from these). I bisected to the following: 794b679a28bb59a4533ae39a7cf945b9d5bbe336 is the first bad commit commit 794b679a28bb59a4533ae39a7cf945b9d5bbe336 Author: Jiaxun Yang <jiaxun.yang(a)flygoat.com> Date: Sat Jun 7 13:43:56 2025 +0100 MIPS: mm: tlb-r4k: Uniquify TLB entries on init commit 35ad7e181541aa5757f9f316768d3e64403ec843 upstream. This reverts cleanly on top of 6.1.158 and the resulting kernel boots normally. I then reproduced this failure on 6.18-rc4. Reverting 35ad7e181541 on top of 6.18-rc4 also results in a normal boot. Let me know if you need any more info! Thanks, Nick

3 weeks, 2 days

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[PATCH v6 02/18] kasan: Unpoison vms[area] addresses with a common tag

by Maciej Wieczor-Retman

From: Maciej Wieczor-Retman <maciej.wieczor-retman(a)intel.com> The problem presented here is related to NUMA systems and tag-based KASAN modes - software and hardware ones. It can be explained in the following points: 1. There can be more than one virtual memory chunk. 2. Chunk's base address has a tag. 3. The base address points at the first chunk and thus inherits the tag of the first chunk. 4. The subsequent chunks will be accessed with the tag from the first chunk. 5. Thus, the subsequent chunks need to have their tag set to match that of the first chunk. Unpoison all vms[]->addr memory and pointers with the same tag to resolve the mismatch. Fixes: 1d96320f8d53 ("kasan, vmalloc: add vmalloc tagging for SW_TAGS") Cc: <stable(a)vger.kernel.org> # 6.1+ Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman(a)intel.com> Tested-by: Baoquan He <bhe(a)redhat.com> --- Changelog v6: - Add Baoquan's tested-by tag. - Move patch to the beginning of the series as it is a fix. - Add fixes tag. mm/kasan/tags.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index ecc17c7c675a..c6b40cbffae3 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -148,12 +148,20 @@ void __kasan_save_free_info(struct kmem_cache *cache, void *object) save_stack_info(cache, object, 0, true); } +/* + * A tag mismatch happens when calculating per-cpu chunk addresses, because + * they all inherit the tag from vms[0]->addr, even when nr_vms is bigger + * than 1. This is a problem because all the vms[]->addr come from separate + * allocations and have different tags so while the calculated address is + * correct the tag isn't. + */ void __kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms) { int area; for (area = 0 ; area < nr_vms ; area++) { kasan_poison(vms[area]->addr, vms[area]->size, - arch_kasan_get_tag(vms[area]->addr), false); + arch_kasan_get_tag(vms[0]->addr), false); + arch_kasan_set_tag(vms[area]->addr, arch_kasan_get_tag(vms[0]->addr)); } } -- 2.51.0

3 weeks, 2 days

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[PATCH v4] block: Remove queue freezing from several sysfs store callbacks

by Bart Van Assche

Freezing the request queue from inside sysfs store callbacks may cause a deadlock in combination with the dm-multipath driver and the queue_if_no_path option. Additionally, freezing the request queue slows down system boot on systems where sysfs attributes are set synchronously. Fix this by removing the blk_mq_freeze_queue() / blk_mq_unfreeze_queue() calls from the store callbacks that do not strictly need these callbacks. This patch may cause a small delay in applying the new settings. This patch affects the following sysfs attributes: * io_poll_delay * io_timeout * nomerges * read_ahead_kb * rq_affinity Here is an example of a deadlock triggered by running test srp/002: task:multipathd Call Trace: <TASK> __schedule+0x8c1/0x1bf0 schedule+0xdd/0x270 schedule_preempt_disabled+0x1c/0x30 __mutex_lock+0xb89/0x1650 mutex_lock_nested+0x1f/0x30 dm_table_set_restrictions+0x823/0xdf0 __bind+0x166/0x590 dm_swap_table+0x2a7/0x490 do_resume+0x1b1/0x610 dev_suspend+0x55/0x1a0 ctl_ioctl+0x3a5/0x7e0 dm_ctl_ioctl+0x12/0x20 __x64_sys_ioctl+0x127/0x1a0 x64_sys_call+0xe2b/0x17d0 do_syscall_64+0x96/0x3a0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> task:(udev-worker) Call Trace: <TASK> __schedule+0x8c1/0x1bf0 schedule+0xdd/0x270 blk_mq_freeze_queue_wait+0xf2/0x140 blk_mq_freeze_queue_nomemsave+0x23/0x30 queue_ra_store+0x14e/0x290 queue_attr_store+0x23e/0x2c0 sysfs_kf_write+0xde/0x140 kernfs_fop_write_iter+0x3b2/0x630 vfs_write+0x4fd/0x1390 ksys_write+0xfd/0x230 __x64_sys_write+0x76/0xc0 x64_sys_call+0x276/0x17d0 do_syscall_64+0x96/0x3a0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> Cc: Christoph Hellwig <hch(a)lst.de> Cc: Ming Lei <ming.lei(a)redhat.com> Cc: Nilay Shroff <nilay(a)linux.ibm.com> Cc: Martin Wilck <mwilck(a)suse.com> Cc: Benjamin Marzinski <bmarzins(a)redhat.com> Cc: stable(a)vger.kernel.org Fixes: af2814149883 ("block: freeze the queue in queue_attr_store") Signed-off-by: Bart Van Assche <bvanassche(a)acm.org> --- Changes compared to v3: - Added two data_race() annotations. Changes compared to v2: - Dropped the controversial patch "block: Restrict the duration of sysfs attribute changes". Changes compared to v1: - Added patch "block: Restrict the duration of sysfs attribute changes". - Remove queue freezing from more sysfs callbacks. block/blk-sysfs.c | 20 +++----------------- 1 file changed, 3 insertions(+), 17 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 76c47fe9b8d6..6eaccd18d8b4 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -143,7 +143,6 @@ queue_ra_store(struct gendisk *disk, const char *page, size_t count) { unsigned long ra_kb; ssize_t ret; - unsigned int memflags; struct request_queue *q = disk->queue; ret = queue_var_store(&ra_kb, page, count); @@ -154,10 +153,8 @@ queue_ra_store(struct gendisk *disk, const char *page, size_t count) * calculated from the queue limits by queue_limits_commit_update. */ mutex_lock(&q->limits_lock); - memflags = blk_mq_freeze_queue(q); - disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10); + data_race(disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10)); mutex_unlock(&q->limits_lock); - blk_mq_unfreeze_queue(q, memflags); return ret; } @@ -375,21 +372,18 @@ static ssize_t queue_nomerges_store(struct gendisk *disk, const char *page, size_t count) { unsigned long nm; - unsigned int memflags; struct request_queue *q = disk->queue; ssize_t ret = queue_var_store(&nm, page, count); if (ret < 0) return ret; - memflags = blk_mq_freeze_queue(q); blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q); blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q); if (nm == 2) blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); else if (nm) blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); - blk_mq_unfreeze_queue(q, memflags); return ret; } @@ -409,7 +403,6 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count) #ifdef CONFIG_SMP struct request_queue *q = disk->queue; unsigned long val; - unsigned int memflags; ret = queue_var_store(&val, page, count); if (ret < 0) @@ -421,7 +414,6 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count) * are accessed individually using atomic test_bit operation. So we * don't grab any lock while updating these flags. */ - memflags = blk_mq_freeze_queue(q); if (val == 2) { blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q); blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); @@ -432,7 +424,6 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count) blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); } - blk_mq_unfreeze_queue(q, memflags); #endif return ret; } @@ -446,11 +437,9 @@ static ssize_t queue_poll_delay_store(struct gendisk *disk, const char *page, static ssize_t queue_poll_store(struct gendisk *disk, const char *page, size_t count) { - unsigned int memflags; ssize_t ret = count; struct request_queue *q = disk->queue; - memflags = blk_mq_freeze_queue(q); if (!(q->limits.features & BLK_FEAT_POLL)) { ret = -EINVAL; goto out; @@ -459,7 +448,6 @@ static ssize_t queue_poll_store(struct gendisk *disk, const char *page, pr_info_ratelimited("writes to the poll attribute are ignored.\n"); pr_info_ratelimited("please use driver specific parameters instead.\n"); out: - blk_mq_unfreeze_queue(q, memflags); return ret; } @@ -472,7 +460,7 @@ static ssize_t queue_io_timeout_show(struct gendisk *disk, char *page) static ssize_t queue_io_timeout_store(struct gendisk *disk, const char *page, size_t count) { - unsigned int val, memflags; + unsigned int val; int err; struct request_queue *q = disk->queue; @@ -480,9 +468,7 @@ static ssize_t queue_io_timeout_store(struct gendisk *disk, const char *page, if (err || val == 0) return -EINVAL; - memflags = blk_mq_freeze_queue(q); - blk_queue_rq_timeout(q, msecs_to_jiffies(val)); - blk_mq_unfreeze_queue(q, memflags); + data_race((blk_queue_rq_timeout(q, msecs_to_jiffies(val)), 0)); return count; }

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