August 2024 - Linux-stable-mirror

[PATCH v4 2/3] x86/sgx: Resolve EAUG race where losing thread returns SIGBUS

by Dmitrii Kuvaiskii

Imagine an mmap()'d file. Two threads touch the same address at the same time and fault. Both allocate a physical page and race to install a PTE for that page. Only one will win the race. The loser frees its page, but still continues handling the fault as a success and returns VM_FAULT_NOPAGE from the fault handler. The same race can happen with SGX. But there's a bug: the loser in the SGX steers into a failure path. The loser EREMOVE's the winner's EPC page, then returns SIGBUS, likely killing the app. Fix the SGX loser's behavior. Change the return code to VM_FAULT_NOPAGE to avoid SIGBUS and call sgx_free_epc_page() which avoids EREMOVE'ing the winner's page and only frees the page that the loser allocated. The race can be illustrated as follows: /* /* * Fault on CPU1 * Fault on CPU2 * on enclave page X * on enclave page X */ */ sgx_vma_fault() { sgx_vma_fault() { xa_load(&encl->page_array) xa_load(&encl->page_array) == NULL --> == NULL --> sgx_encl_eaug_page() { sgx_encl_eaug_page() { ... ... /* /* * alloc encl_page * alloc encl_page */ */ mutex_lock(&encl->lock); /* * alloc EPC page */ epc_page = sgx_alloc_epc_page(...); /* * add page to enclave's xarray */ xa_insert(&encl->page_array, ...); /* * add page to enclave via EAUG * (page is in pending state) */ /* * add PTE entry */ vmf_insert_pfn(...); mutex_unlock(&encl->lock); return VM_FAULT_NOPAGE; } } /* * All good up to here: enclave page * successfully added to enclave, * ready for EACCEPT from user space */ mutex_lock(&encl->lock); /* * alloc EPC page */ epc_page = sgx_alloc_epc_page(...); /* * add page to enclave's xarray, * this fails with -EBUSY as this * page was already added by CPU2 */ xa_insert(&encl->page_array, ...); err_out_shrink: sgx_encl_free_epc_page(epc_page) { /* * remove page via EREMOVE * * *BUG*: page added by CPU2 is * yanked from enclave while it * remains accessible from OS * perspective (PTE installed) */ /* * free EPC page */ sgx_free_epc_page(epc_page); } mutex_unlock(&encl->lock); /* * *BUG*: SIGBUS is returned * for a valid enclave page */ return VM_FAULT_SIGBUS; } } Fixes: 5a90d2c3f5ef ("x86/sgx: Support adding of pages to an initialized enclave") Cc: stable(a)vger.kernel.org Reported-by: Marcelina Kościelnicka <mwk(a)invisiblethingslab.com> Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Dmitrii Kuvaiskii <dmitrii.kuvaiskii(a)intel.com> Reviewed-by: Haitao Huang <haitao.huang(a)linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko(a)kernel.org> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index c0a3c00284c8..9f7f9e57cdeb 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -380,8 +380,11 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma, * If ret == -EBUSY then page was created in another flow while * running without encl->lock */ - if (ret) + if (ret) { + if (ret == -EBUSY) + vmret = VM_FAULT_NOPAGE; goto err_out_shrink; + } pginfo.secs = (unsigned long)sgx_get_epc_virt_addr(encl->secs.epc_page); pginfo.addr = encl_page->desc & PAGE_MASK; @@ -417,7 +420,7 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma, err_out_shrink: sgx_encl_shrink(encl, va_page); err_out_epc: - sgx_encl_free_epc_page(epc_page); + sgx_free_epc_page(epc_page); err_out_unlock: mutex_unlock(&encl->lock); kfree(encl_page); -- 2.43.0

8 months, 3 weeks

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[PATCH v4 1/3] x86/sgx: Split SGX_ENCL_PAGE_BEING_RECLAIMED into two flags

by Dmitrii Kuvaiskii

SGX_ENCL_PAGE_BEING_RECLAIMED flag is set when the enclave page is being reclaimed (moved to the backing store). This flag however has two logical meanings: 1. Don't attempt to load the enclave page (the page is busy). 2. Don't attempt to remove the PCMD page corresponding to this enclave page (the PCMD page is busy). To reflect these two meanings, split SGX_ENCL_PAGE_BEING_RECLAIMED into two flags: SGX_ENCL_PAGE_BUSY and SGX_ENCL_PAGE_PCMD_BUSY. Currently, both flags are set only when the enclave page is being reclaimed. A future commit will introduce a new case when the enclave page is being removed; this new case will set only the SGX_ENCL_PAGE_BUSY flag. Cc: stable(a)vger.kernel.org Signed-off-by: Dmitrii Kuvaiskii <dmitrii.kuvaiskii(a)intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 16 +++++++--------- arch/x86/kernel/cpu/sgx/encl.h | 10 ++++++++-- arch/x86/kernel/cpu/sgx/main.c | 4 ++-- 3 files changed, 17 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 279148e72459..c0a3c00284c8 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -46,10 +46,10 @@ static int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_ind * a check if an enclave page sharing the PCMD page is in the process of being * reclaimed. * - * The reclaimer sets the SGX_ENCL_PAGE_BEING_RECLAIMED flag when it - * intends to reclaim that enclave page - it means that the PCMD page - * associated with that enclave page is about to get some data and thus - * even if the PCMD page is empty, it should not be truncated. + * The reclaimer sets the SGX_ENCL_PAGE_PCMD_BUSY flag when it intends to + * reclaim that enclave page - it means that the PCMD page associated with that + * enclave page is about to get some data and thus even if the PCMD page is + * empty, it should not be truncated. * * Context: Enclave mutex (&sgx_encl->lock) must be held. * Return: 1 if the reclaimer is about to write to the PCMD page @@ -77,8 +77,7 @@ static int reclaimer_writing_to_pcmd(struct sgx_encl *encl, * Stop when reaching the SECS page - it does not * have a page_array entry and its reclaim is * started and completed with enclave mutex held so - * it does not use the SGX_ENCL_PAGE_BEING_RECLAIMED - * flag. + * it does not use the SGX_ENCL_PAGE_PCMD_BUSY flag. */ if (addr == encl->base + encl->size) break; @@ -91,8 +90,7 @@ static int reclaimer_writing_to_pcmd(struct sgx_encl *encl, * VA page slot ID uses same bit as the flag so it is important * to ensure that the page is not already in backing store. */ - if (entry->epc_page && - (entry->desc & SGX_ENCL_PAGE_BEING_RECLAIMED)) { + if (entry->epc_page && (entry->desc & SGX_ENCL_PAGE_PCMD_BUSY)) { reclaimed = 1; break; } @@ -257,7 +255,7 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, /* Entry successfully located. */ if (entry->epc_page) { - if (entry->desc & SGX_ENCL_PAGE_BEING_RECLAIMED) + if (entry->desc & SGX_ENCL_PAGE_BUSY) return ERR_PTR(-EBUSY); return entry; diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index f94ff14c9486..11b09899cd92 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -22,8 +22,14 @@ /* 'desc' bits holding the offset in the VA (version array) page. */ #define SGX_ENCL_PAGE_VA_OFFSET_MASK GENMASK_ULL(11, 3) -/* 'desc' bit marking that the page is being reclaimed. */ -#define SGX_ENCL_PAGE_BEING_RECLAIMED BIT(3) +/* 'desc' bit indicating that the page is busy (e.g. being reclaimed). */ +#define SGX_ENCL_PAGE_BUSY BIT(2) + +/* + * 'desc' bit indicating that PCMD page associated with the enclave page is + * busy (e.g. because the enclave page is being reclaimed). + */ +#define SGX_ENCL_PAGE_PCMD_BUSY BIT(3) struct sgx_encl_page { unsigned long desc; diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 166692f2d501..e94b09c43673 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -204,7 +204,7 @@ static void sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot; int ret; - encl_page->desc &= ~SGX_ENCL_PAGE_BEING_RECLAIMED; + encl_page->desc &= ~(SGX_ENCL_PAGE_BUSY | SGX_ENCL_PAGE_PCMD_BUSY); va_page = list_first_entry(&encl->va_pages, struct sgx_va_page, list); @@ -340,7 +340,7 @@ static void sgx_reclaim_pages(void) goto skip; } - encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED; + encl_page->desc |= SGX_ENCL_PAGE_BUSY | SGX_ENCL_PAGE_PCMD_BUSY; mutex_unlock(&encl_page->encl->lock); continue; -- 2.43.0

8 months, 3 weeks

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[PATCH 6.6.y 0/13] arm64: errata: Speculative SSBS workaround

by Mark Rutland

Hi, This series is a v6.6-only backport (based on v6.6.44) of the upstream workaround for SSBS errata on Arm Ltd CPUs, as affected parts are likely to be used with stable kernels. This does not apply to earlier stable trees, which will receive a separate backport. The errata mean that an MSR to the SSBS special-purpose register does not affect subsequent speculative instructions, permitting speculative store bypassing for a window of time. The upstream support was original posted as: * https://lore.kernel.org/linux-arm-kernel/20240508081400.235362-1-mark.rutla… "arm64: errata: Add workaround for Arm errata 3194386 and 3312417" Present in v6.10 * https://lore.kernel.org/linux-arm-kernel/20240603111812.1514101-1-mark.rutl… "arm64: errata: Expand speculative SSBS workaround" Present in v6.11-rc1 * https://lore.kernel.org/linux-arm-kernel/20240801101803.1982459-1-mark.rutl… "arm64: errata: Expand speculative SSBS workaround (again)" Present in v6.11-rc2 This backport applies the patches which are not present in v6.6.y, and as prerequisites backports the addition of the Neoverse-V2 MIDR values and the restoration of the spec_bar() macro. I have tested the backport (when applied to v6.6.44), ensuring that the detection logic works and that the HWCAP and string in /proc/cpuinfo are both hidden when the relevant errata are detected. Mark.Besar Wicaksono (1): arm64: Add Neoverse-V2 part Mark Rutland (12): arm64: barrier: Restore spec_bar() macro arm64: cputype: Add Cortex-X4 definitions arm64: cputype: Add Neoverse-V3 definitions arm64: errata: Add workaround for Arm errata 3194386 and 3312417 arm64: cputype: Add Cortex-X3 definitions arm64: cputype: Add Cortex-A720 definitions arm64: cputype: Add Cortex-X925 definitions arm64: errata: Unify speculative SSBS errata logic arm64: errata: Expand speculative SSBS workaround arm64: cputype: Add Cortex-X1C definitions arm64: cputype: Add Cortex-A725 definitions arm64: errata: Expand speculative SSBS workaround (again) Documentation/arch/arm64/silicon-errata.rst | 36 +++++++++++++++++++ arch/arm64/Kconfig | 38 +++++++++++++++++++++ arch/arm64/include/asm/barrier.h | 4 +++ arch/arm64/include/asm/cputype.h | 16 +++++++++ arch/arm64/kernel/cpu_errata.c | 31 +++++++++++++++++ arch/arm64/kernel/cpufeature.c | 12 +++++++ arch/arm64/kernel/proton-pack.c | 12 +++++++ arch/arm64/tools/cpucaps | 1 + 8 files changed, 150 insertions(+) -- 2.30.2

8 months, 3 weeks

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[PATCH] drm/amdgpu: Check if NBIO funcs are NULL in amdgpu_device_baco_exit

by Alex Deucher

From: Friedrich Vock <friedrich.vock(a)gmx.de> The special case for VM passthrough doesn't check adev->nbio.funcs before dereferencing it. If GPUs that don't have an NBIO block are passed through, this leads to a NULL pointer dereference on startup. Signed-off-by: Friedrich Vock <friedrich.vock(a)gmx.de> Fixes: 1bece222eabe ("drm/amdgpu: Clear doorbell interrupt status for Sienna Cichlid") Cc: Alex Deucher <alexander.deucher(a)amd.com> Cc: Christian König <christian.koenig(a)amd.com> Acked-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3558 Cc: stable(a)vger.kernel.org # 5.15.x (cherry picked from commit 0cdb3f9740844b9d95ca413e3fcff11f81223ecf) --- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index 5f6c32ec674d..300d3b236bb3 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -5531,7 +5531,7 @@ int amdgpu_device_baco_exit(struct drm_device *dev) adev->nbio.funcs->enable_doorbell_interrupt) adev->nbio.funcs->enable_doorbell_interrupt(adev, true); - if (amdgpu_passthrough(adev) && + if (amdgpu_passthrough(adev) && adev->nbio.funcs && adev->nbio.funcs->clear_doorbell_interrupt) adev->nbio.funcs->clear_doorbell_interrupt(adev); -- 2.46.0

8 months, 3 weeks

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[PATCH 1/1] xhci: Fix Panther point NULL pointer deref at full-speed re-enumeration

by Mathias Nyman

re-enumerating full-speed devices after a failed address device command can trigger a NULL pointer dereference. Full-speed devices may need to reconfigure the endpoint 0 Max Packet Size value during enumeration. Usb core calls usb_ep0_reinit() in this case, which ends up calling xhci_configure_endpoint(). On Panther point xHC the xhci_configure_endpoint() function will additionally check and reserve bandwidth in software. Other hosts do this in hardware If xHC address device command fails then a new xhci_virt_device structure is allocated as part of re-enabling the slot, but the bandwidth table pointers are not set up properly here. This triggers the NULL pointer dereference the next time usb_ep0_reinit() is called and xhci_configure_endpoint() tries to check and reserve bandwidth [46710.713538] usb 3-1: new full-speed USB device number 5 using xhci_hcd [46710.713699] usb 3-1: Device not responding to setup address. [46710.917684] usb 3-1: Device not responding to setup address. [46711.125536] usb 3-1: device not accepting address 5, error -71 [46711.125594] BUG: kernel NULL pointer dereference, address: 0000000000000008 [46711.125600] #PF: supervisor read access in kernel mode [46711.125603] #PF: error_code(0x0000) - not-present page [46711.125606] PGD 0 P4D 0 [46711.125610] Oops: Oops: 0000 [#1] PREEMPT SMP PTI [46711.125615] CPU: 1 PID: 25760 Comm: kworker/1:2 Not tainted 6.10.3_2 #1 [46711.125620] Hardware name: Gigabyte Technology Co., Ltd. [46711.125623] Workqueue: usb_hub_wq hub_event [usbcore] [46711.125668] RIP: 0010:xhci_reserve_bandwidth (drivers/usb/host/xhci.c Fix this by making sure bandwidth table pointers are set up correctly after a failed address device command, and additionally by avoiding checking for bandwidth in cases like this where no actual endpoints are added or removed, i.e. only context for default control endpoint 0 is evaluated. Reported-by: Karel Balej <balejk(a)matfyz.cz> Closes: https://lore.kernel.org/linux-usb/D3CKQQAETH47.1MUO22RTCH2O3@matfyz.cz/ Cc: stable(a)vger.kernel.org Fixes: 651aaf36a7d7 ("usb: xhci: Handle USB transaction error on address command") Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 0a8cf6c17f82..efdf4c228b8c 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -2837,7 +2837,7 @@ static int xhci_configure_endpoint(struct xhci_hcd *xhci, xhci->num_active_eps); return -ENOMEM; } - if ((xhci->quirks & XHCI_SW_BW_CHECKING) && + if ((xhci->quirks & XHCI_SW_BW_CHECKING) && !ctx_change && xhci_reserve_bandwidth(xhci, virt_dev, command->in_ctx)) { if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK)) xhci_free_host_resources(xhci, ctrl_ctx); @@ -4200,8 +4200,10 @@ static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev, mutex_unlock(&xhci->mutex); ret = xhci_disable_slot(xhci, udev->slot_id); xhci_free_virt_device(xhci, udev->slot_id); - if (!ret) - xhci_alloc_dev(hcd, udev); + if (!ret) { + if (xhci_alloc_dev(hcd, udev) == 1) + xhci_setup_addressable_virt_dev(xhci, udev); + } kfree(command->completion); kfree(command); return -EPROTO; -- 2.25.1

8 months, 3 weeks

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[PATCH] Revert "ata: libata-scsi: Honor the D_SENSE bit for CK_COND=1 and no error"

by Niklas Cassel

This reverts commit 28ab9769117ca944cb6eb537af5599aa436287a4. Sense data can be in either fixed format or descriptor format. SAT-6 revision 1, "10.4.6 Control mode page", defines the D_SENSE bit: "The SATL shall support this bit as defined in SPC-5 with the following exception: if the D_ SENSE bit is set to zero (i.e., fixed format sense data), then the SATL should return fixed format sense data for ATA PASS-THROUGH commands." The libata SATL has always kept D_SENSE set to zero by default. (It is however possible to change the value using a MODE SELECT SG_IO command.) Failed ATA PASS-THROUGH commands correctly respected the D_SENSE bit, however, successful ATA PASS-THROUGH commands incorrectly returned the sense data in descriptor format (regardless of the D_SENSE bit). Commit 28ab9769117c ("ata: libata-scsi: Honor the D_SENSE bit for CK_COND=1 and no error") fixed this bug for successful ATA PASS-THROUGH commands. However, after commit 28ab9769117c ("ata: libata-scsi: Honor the D_SENSE bit for CK_COND=1 and no error"), there were bug reports that hdparm, hddtemp, and udisks were no longer working as expected. These applications incorrectly assume the returned sense data is in descriptor format, without even looking at the RESPONSE CODE field in the returned sense data (to see which format the returned sense data is in). Considering that there will be broken versions of these applications around roughly forever, we are stuck with being bug compatible with older kernels. Cc: stable(a)vger.kernel.org # 4.19+ Reported-by: Stephan Eisvogel <eisvogel(a)seitics.de> Reported-by: Christian Heusel <christian(a)heusel.eu> Closes: https://lore.kernel.org/linux-ide/0bf3f2f0-0fc6-4ba5-a420-c0874ef82d64@heus… Fixes: 28ab9769117c ("ata: libata-scsi: Honor the D_SENSE bit for CK_COND=1 and no error") Signed-off-by: Niklas Cassel <cassel(a)kernel.org> --- drivers/ata/libata-scsi.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index d6f5e25e1ed8..473e00a58a8b 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -951,8 +951,19 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc) &sense_key, &asc, &ascq); ata_scsi_set_sense(qc->dev, cmd, sense_key, asc, ascq); } else { - /* ATA PASS-THROUGH INFORMATION AVAILABLE */ - ata_scsi_set_sense(qc->dev, cmd, RECOVERED_ERROR, 0, 0x1D); + /* + * ATA PASS-THROUGH INFORMATION AVAILABLE + * + * Note: we are supposed to call ata_scsi_set_sense(), which + * respects the D_SENSE bit, instead of unconditionally + * generating the sense data in descriptor format. However, + * because hdparm, hddtemp, and udisks incorrectly assume sense + * data in descriptor format, without even looking at the + * RESPONSE CODE field in the returned sense data (to see which + * format the returned sense data is in), we are stuck with + * being bug compatible with older kernels. + */ + scsi_build_sense(cmd, 1, RECOVERED_ERROR, 0, 0x1D); } } -- 2.46.0

8 months, 3 weeks

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Re: Patch "ext4: convert ext4_da_do_write_end() to take a folio" has been added to the 6.6-stable tree

by Matthew Wilcox

On Thu, Aug 15, 2024 at 08:22:16AM -0400, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > ext4: convert ext4_da_do_write_end() to take a folio > > to the 6.6-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: > ext4-convert-ext4_da_do_write_end-to-take-a-folio.patch > and it can be found in the queue-6.6 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. I'd think you'd want to backport 83f4414b8f84 to before folios existing, so you may as well use the same patch for 6.6 as you'd want to use for those older kernels. ie: if (unlikely(!page_buffers(page))) { unlock_page(page); put_page(page); return -EIO; } but maybe this has already been discussed and I wasn't cc'd on that discussion.

8 months, 3 weeks

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[PATCH 0/3] drm/mediatek: fixes for ovl_adaptor

by Javier Carrasco

The main fix is a possible memory leak on an early exit in the for_each_child_of_node() loop. That fix has been divided into a patch that can be backported (a simple of_node_put()), and another one that uses the scoped variant of the macro, removing the need for any of_node_put(). That prevents mistakes if new break/return instructions are added, but the macro might not be available in older kernels. When at it, an unused header has been dropped. Signed-off-by: Javier Carrasco <javier.carrasco.cruz(a)gmail.com> --- Javier Carrasco (3): drm/mediatek: ovl_adaptor: drop unused mtk_crtc.h header drm/mediatek: ovl_adaptor: add missing of_node_put() drm/mediatek: ovl_adaptor: use scoped variant of for_each_child_of_node() drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- base-commit: f76698bd9a8ca01d3581236082d786e9a6b72bb7 change-id: 20240624-mtk_disp_ovl_adaptor_scoped-0702a6b23443 Best regards, -- Javier Carrasco <javier.carrasco.cruz(a)gmail.com>

8 months, 3 weeks

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Re: [PATCH 6.10 00/22] 6.10.6-rc1 review

by Ronald Warsow

Hi Greg no regressions here on x86_64 (RKL, Intel 11th Gen. CPU) Thanks Tested-by: Ronald Warsow <rwarsow(a)gmx.de>

8 months, 3 weeks

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[tip: locking/urgent] rtmutex: Drop rt_mutex::wait_lock before scheduling

by tip-bot2 for Roland Xu

The following commit has been merged into the locking/urgent branch of tip: Commit-ID: d33d26036a0274b472299d7dcdaa5fb34329f91b Gitweb: https://git.kernel.org/tip/d33d26036a0274b472299d7dcdaa5fb34329f91b Author: Roland Xu <mu001999(a)outlook.com> AuthorDate: Thu, 15 Aug 2024 10:58:13 +08:00 Committer: Thomas Gleixner <tglx(a)linutronix.de> CommitterDate: Thu, 15 Aug 2024 15:38:53 +02:00 rtmutex: Drop rt_mutex::wait_lock before scheduling rt_mutex_handle_deadlock() is called with rt_mutex::wait_lock held. In the good case it returns with the lock held and in the deadlock case it emits a warning and goes into an endless scheduling loop with the lock held, which triggers the 'scheduling in atomic' warning. Unlock rt_mutex::wait_lock in the dead lock case before issuing the warning and dropping into the schedule for ever loop. [ tglx: Moved unlock before the WARN(), removed the pointless comment, massaged changelog, added Fixes tag ] Fixes: 3d5c9340d194 ("rtmutex: Handle deadlock detection smarter") Signed-off-by: Roland Xu <mu001999(a)outlook.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300M… --- kernel/locking/rtmutex.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 88d08ee..fba1229 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1644,6 +1644,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock, } static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex_base *lock, struct rt_mutex_waiter *w) { /* @@ -1656,10 +1657,10 @@ static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, if (build_ww_mutex() && w->ww_ctx) return; - /* - * Yell loudly and stop the task right here. - */ + raw_spin_unlock_irq(&lock->wait_lock); + WARN(1, "rtmutex deadlock detected\n"); + while (1) { set_current_state(TASK_INTERRUPTIBLE); rt_mutex_schedule(); @@ -1713,7 +1714,7 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, } else { __set_current_state(TASK_RUNNING); remove_waiter(lock, waiter); - rt_mutex_handle_deadlock(ret, chwalk, waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, waiter); } /*

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