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[PATCH v5.10] cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()

by Shivani Agarwal

From: Henry Martin <bsdhenrymartin(a)gmail.com> [ Upstream commit 484d3f15cc6cbaa52541d6259778e715b2c83c54 ] cpufreq_cpu_get_raw() can return NULL when the target CPU is not present in the policy->cpus mask. scmi_cpufreq_get_rate() does not check for this case, which results in a NULL pointer dereference. Add NULL check after cpufreq_cpu_get_raw() to prevent this issue. Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol") Signed-off-by: Henry Martin <bsdhenrymartin(a)gmail.com> Acked-by: Sudeep Holla <sudeep.holla(a)arm.com> Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> [Shivani: Modified to apply on 5.10.y] Signed-off-by: Shivani Agarwal <shivani.agarwal(a)broadcom.com> --- drivers/cpufreq/scmi-cpufreq.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c index bb1389f27..6b65d537c 100644 --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -29,12 +29,18 @@ static const struct scmi_handle *handle; static unsigned int scmi_cpufreq_get_rate(unsigned int cpu) { - struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); + struct cpufreq_policy *policy; + struct scmi_data *priv; const struct scmi_perf_ops *perf_ops = handle->perf_ops; - struct scmi_data *priv = policy->driver_data; unsigned long rate; int ret; + policy = cpufreq_cpu_get_raw(cpu); + if (unlikely(!policy)) + return 0; + + priv = policy->driver_data; + ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false); if (ret) return 0; -- 2.40.4

5 days

[PATCH 6.12-stable] x86/microcode/AMD: Select which microcode patch to load

by Borislav Petkov

From: "Borislav Petkov (AMD)" <bp(a)alien8.de> Commit 8d171045069c804e5ffaa18be590c42c6af0cf3f upstream. All microcode patches up to the proper BIOS Entrysign fix are loaded only after the sha256 signature carried in the driver has been verified. Microcode patches after the Entrysign fix has been applied, do not need that signature verification anymore. In order to not abandon machines which haven't received the BIOS update yet, add the capability to select which microcode patch to load. The corresponding microcode container supplied through firmware-linux has been modified to carry two patches per CPU type (family/model/stepping) so that the proper one gets selected. Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Tested-by: Waiman Long <longman(a)redhat.com> Link: https://patch.msgid.link/20251027133818.4363-1-bp@kernel.org --- arch/x86/kernel/cpu/microcode/amd.c | 104 ++++++++++++++++++---------- 1 file changed, 67 insertions(+), 37 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 7e997360223b..6330023176e0 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -174,50 +174,61 @@ static u32 cpuid_to_ucode_rev(unsigned int val) return p.ucode_rev; } +static u32 get_cutoff_revision(u32 rev) +{ + switch (rev >> 8) { + case 0x80012: return 0x8001277; break; + case 0x80082: return 0x800820f; break; + case 0x83010: return 0x830107c; break; + case 0x86001: return 0x860010e; break; + case 0x86081: return 0x8608108; break; + case 0x87010: return 0x8701034; break; + case 0x8a000: return 0x8a0000a; break; + case 0xa0010: return 0xa00107a; break; + case 0xa0011: return 0xa0011da; break; + case 0xa0012: return 0xa001243; break; + case 0xa0082: return 0xa00820e; break; + case 0xa1011: return 0xa101153; break; + case 0xa1012: return 0xa10124e; break; + case 0xa1081: return 0xa108109; break; + case 0xa2010: return 0xa20102f; break; + case 0xa2012: return 0xa201212; break; + case 0xa4041: return 0xa404109; break; + case 0xa5000: return 0xa500013; break; + case 0xa6012: return 0xa60120a; break; + case 0xa7041: return 0xa704109; break; + case 0xa7052: return 0xa705208; break; + case 0xa7080: return 0xa708009; break; + case 0xa70c0: return 0xa70C009; break; + case 0xaa001: return 0xaa00116; break; + case 0xaa002: return 0xaa00218; break; + case 0xb0021: return 0xb002146; break; + case 0xb0081: return 0xb008111; break; + case 0xb1010: return 0xb101046; break; + case 0xb2040: return 0xb204031; break; + case 0xb4040: return 0xb404031; break; + case 0xb4041: return 0xb404101; break; + case 0xb6000: return 0xb600031; break; + case 0xb6080: return 0xb608031; break; + case 0xb7000: return 0xb700031; break; + default: break; + + } + return 0; +} + static bool need_sha_check(u32 cur_rev) { + u32 cutoff; + if (!cur_rev) { cur_rev = cpuid_to_ucode_rev(bsp_cpuid_1_eax); pr_info_once("No current revision, generating the lowest one: 0x%x\n", cur_rev); } - switch (cur_rev >> 8) { - case 0x80012: return cur_rev <= 0x8001277; break; - case 0x80082: return cur_rev <= 0x800820f; break; - case 0x83010: return cur_rev <= 0x830107c; break; - case 0x86001: return cur_rev <= 0x860010e; break; - case 0x86081: return cur_rev <= 0x8608108; break; - case 0x87010: return cur_rev <= 0x8701034; break; - case 0x8a000: return cur_rev <= 0x8a0000a; break; - case 0xa0010: return cur_rev <= 0xa00107a; break; - case 0xa0011: return cur_rev <= 0xa0011da; break; - case 0xa0012: return cur_rev <= 0xa001243; break; - case 0xa0082: return cur_rev <= 0xa00820e; break; - case 0xa1011: return cur_rev <= 0xa101153; break; - case 0xa1012: return cur_rev <= 0xa10124e; break; - case 0xa1081: return cur_rev <= 0xa108109; break; - case 0xa2010: return cur_rev <= 0xa20102f; break; - case 0xa2012: return cur_rev <= 0xa201212; break; - case 0xa4041: return cur_rev <= 0xa404109; break; - case 0xa5000: return cur_rev <= 0xa500013; break; - case 0xa6012: return cur_rev <= 0xa60120a; break; - case 0xa7041: return cur_rev <= 0xa704109; break; - case 0xa7052: return cur_rev <= 0xa705208; break; - case 0xa7080: return cur_rev <= 0xa708009; break; - case 0xa70c0: return cur_rev <= 0xa70C009; break; - case 0xaa001: return cur_rev <= 0xaa00116; break; - case 0xaa002: return cur_rev <= 0xaa00218; break; - case 0xb0021: return cur_rev <= 0xb002146; break; - case 0xb0081: return cur_rev <= 0xb008111; break; - case 0xb1010: return cur_rev <= 0xb101046; break; - case 0xb2040: return cur_rev <= 0xb204031; break; - case 0xb4040: return cur_rev <= 0xb404031; break; - case 0xb4041: return cur_rev <= 0xb404101; break; - case 0xb6000: return cur_rev <= 0xb600031; break; - case 0xb6080: return cur_rev <= 0xb608031; break; - case 0xb7000: return cur_rev <= 0xb700031; break; - default: break; - } + cutoff = get_cutoff_revision(cur_rev); + if (cutoff) + return cur_rev <= cutoff; pr_info("You should not be seeing this. Please send the following couple of lines to x86-<at>-kernel.org\n"); pr_info("CPUID(1).EAX: 0x%x, current revision: 0x%x\n", bsp_cpuid_1_eax, cur_rev); @@ -468,6 +479,7 @@ static int verify_patch(const u8 *buf, size_t buf_size, u32 *patch_size) { u8 family = x86_family(bsp_cpuid_1_eax); struct microcode_header_amd *mc_hdr; + u32 cur_rev, cutoff, patch_rev; unsigned int ret; u32 sh_psize; u16 proc_id; @@ -511,6 +523,24 @@ static int verify_patch(const u8 *buf, size_t buf_size, u32 *patch_size) if (patch_fam != family) return 1; + cur_rev = get_patch_level(); + + /* No cutoff revision means old/unaffected by signing algorithm weakness => matches */ + cutoff = get_cutoff_revision(cur_rev); + if (!cutoff) + goto ok; + + patch_rev = mc_hdr->patch_id; + + if (cur_rev <= cutoff && patch_rev <= cutoff) + goto ok; + + if (cur_rev > cutoff && patch_rev > cutoff) + goto ok; + + return 1; +ok: + return 0; } -- 2.51.0

5 days

FAILED: patch "[PATCH] ntfs: Do not overwrite uptodate pages" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

5 days

[PATCH 2/4] ASoC: codecs: wsa881x: fix unnecessary initialisation

by Johan Hovold

The soundwire update_status() callback may be called multiple times with the same ATTACHED status but initialisation should only be done when transitioning from UNATTACHED to ATTACHED. Fixes: a0aab9e1404a ("ASoC: codecs: add wsa881x amplifier support") Cc: stable(a)vger.kernel.org # 5.6 Cc: Srinivas Kandagatla <srini(a)kernel.org> Signed-off-by: Johan Hovold <johan(a)kernel.org> --- sound/soc/codecs/wsa881x.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/sound/soc/codecs/wsa881x.c b/sound/soc/codecs/wsa881x.c index d7aca6567c2d..2fc234adca5f 100644 --- a/sound/soc/codecs/wsa881x.c +++ b/sound/soc/codecs/wsa881x.c @@ -678,6 +678,7 @@ struct wsa881x_priv { */ unsigned int sd_n_val; int active_ports; + bool hw_init; bool port_prepared[WSA881X_MAX_SWR_PORTS]; bool port_enable[WSA881X_MAX_SWR_PORTS]; }; @@ -687,6 +688,9 @@ static void wsa881x_init(struct wsa881x_priv *wsa881x) struct regmap *rm = wsa881x->regmap; unsigned int val = 0; + if (wsa881x->hw_init) + return; + regmap_register_patch(wsa881x->regmap, wsa881x_rev_2_0, ARRAY_SIZE(wsa881x_rev_2_0)); @@ -724,6 +728,8 @@ static void wsa881x_init(struct wsa881x_priv *wsa881x) regmap_update_bits(rm, WSA881X_OTP_REG_28, 0x3F, 0x3A); regmap_update_bits(rm, WSA881X_BONGO_RESRV_REG1, 0xFF, 0xB2); regmap_update_bits(rm, WSA881X_BONGO_RESRV_REG2, 0xFF, 0x05); + + wsa881x->hw_init = true; } static int wsa881x_component_probe(struct snd_soc_component *comp) @@ -1067,6 +1073,9 @@ static int wsa881x_update_status(struct sdw_slave *slave, { struct wsa881x_priv *wsa881x = dev_get_drvdata(&slave->dev); + if (status == SDW_SLAVE_UNATTACHED) + wsa881x->hw_init = false; + if (status == SDW_SLAVE_ATTACHED && slave->dev_num > 0) wsa881x_init(wsa881x); -- 2.51.2

5 days

[PATCH 1/4] ASoC: codecs: wsa883x: fix unnecessary initialisation

by Johan Hovold

The soundwire update_status() callback may be called multiple times with the same ATTACHED status but initialisation should only be done when transitioning from UNATTACHED to ATTACHED. This avoids repeated initialisation of the codecs during boot of machines like the Lenovo ThinkPad X13s: [ 11.614523] wsa883x-codec sdw:1:0:0217:0202:00:1: WSA883X Version 1_1, Variant: WSA8835_V2 [ 11.618022] wsa883x-codec sdw:1:0:0217:0202:00:1: WSA883X Version 1_1, Variant: WSA8835_V2 [ 11.621377] wsa883x-codec sdw:1:0:0217:0202:00:1: WSA883X Version 1_1, Variant: WSA8835_V2 [ 11.624065] wsa883x-codec sdw:1:0:0217:0202:00:1: WSA883X Version 1_1, Variant: WSA8835_V2 [ 11.631382] wsa883x-codec sdw:1:0:0217:0202:00:2: WSA883X Version 1_1, Variant: WSA8835_V2 [ 11.634424] wsa883x-codec sdw:1:0:0217:0202:00:2: WSA883X Version 1_1, Variant: WSA8835_V2 Fixes: 43b8c7dc85a1 ("ASoC: codecs: add wsa883x amplifier support") Cc: stable(a)vger.kernel.org # 6.0 Cc: Srinivas Kandagatla <srini(a)kernel.org> Signed-off-by: Johan Hovold <johan(a)kernel.org> --- sound/soc/codecs/wsa883x.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/sound/soc/codecs/wsa883x.c b/sound/soc/codecs/wsa883x.c index c3046e260cb9..3ffea56aeb0f 100644 --- a/sound/soc/codecs/wsa883x.c +++ b/sound/soc/codecs/wsa883x.c @@ -475,6 +475,7 @@ struct wsa883x_priv { int active_ports; int dev_mode; int comp_offset; + bool hw_init; /* * Protects temperature reading code (related to speaker protection) and * fields: temperature and pa_on. @@ -1043,6 +1044,9 @@ static int wsa883x_init(struct wsa883x_priv *wsa883x) struct regmap *regmap = wsa883x->regmap; int variant, version, ret; + if (wsa883x->hw_init) + return 0; + ret = regmap_read(regmap, WSA883X_OTP_REG_0, &variant); if (ret) return ret; @@ -1085,6 +1089,8 @@ static int wsa883x_init(struct wsa883x_priv *wsa883x) wsa883x->comp_offset); } + wsa883x->hw_init = true; + return 0; } @@ -1093,6 +1099,9 @@ static int wsa883x_update_status(struct sdw_slave *slave, { struct wsa883x_priv *wsa883x = dev_get_drvdata(&slave->dev); + if (status == SDW_SLAVE_UNATTACHED) + wsa883x->hw_init = false; + if (status == SDW_SLAVE_ATTACHED && slave->dev_num > 0) return wsa883x_init(wsa883x); -- 2.51.2

5 days

[PATCH 3/4] ASoC: codecs: wsa884x: fix codec initialisation

by Johan Hovold

The soundwire update_status() callback may be called multiple times with the same ATTACHED status but initialisation should only be done when transitioning from UNATTACHED to ATTACHED. Fix the inverted hw_init flag which was set to false instead of true after initialisation which defeats its purpose and may result in repeated unnecessary initialisation. Similarly, the initial state of the flag was also inverted so that the codec would only be initialised and brought out of regmap cache only mode if its status first transitions to UNATTACHED. Fixes: aa21a7d4f68a ("ASoC: codecs: wsa884x: Add WSA884x family of speakers") Cc: stable(a)vger.kernel.org # 6.5 Cc: Krzysztof Kozlowski <krzk(a)kernel.org> Signed-off-by: Johan Hovold <johan(a)kernel.org> --- sound/soc/codecs/wsa884x.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/sound/soc/codecs/wsa884x.c b/sound/soc/codecs/wsa884x.c index 887edd2be705..6c6b497657d0 100644 --- a/sound/soc/codecs/wsa884x.c +++ b/sound/soc/codecs/wsa884x.c @@ -1534,7 +1534,7 @@ static void wsa884x_init(struct wsa884x_priv *wsa884x) wsa884x_set_gain_parameters(wsa884x); - wsa884x->hw_init = false; + wsa884x->hw_init = true; } static int wsa884x_update_status(struct sdw_slave *slave, @@ -2109,7 +2109,6 @@ static int wsa884x_probe(struct sdw_slave *pdev, /* Start in cache-only until device is enumerated */ regcache_cache_only(wsa884x->regmap, true); - wsa884x->hw_init = true; if (IS_REACHABLE(CONFIG_HWMON)) { struct device *hwmon; -- 2.51.2

5 days

FAILED: patch "[PATCH] iommu: disable SVA when CONFIG_X86 is set" 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 72f98ef9a4be30d2a60136dd6faee376f780d06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010504-amigo-tag-afbd@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 72f98ef9a4be30d2a60136dd6faee376f780d06c Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Wed, 22 Oct 2025 16:26:27 +0800 Subject: [PATCH] iommu: disable SVA when CONFIG_X86 is set Patch series "Fix stale IOTLB entries for kernel address space", v7. This proposes a fix for a security vulnerability related to IOMMU Shared Virtual Addressing (SVA). In an SVA context, an IOMMU can cache kernel page table entries. When a kernel page table page is freed and reallocated for another purpose, the IOMMU might still hold stale, incorrect entries. This can be exploited to cause a use-after-free or write-after-free condition, potentially leading to privilege escalation or data corruption. This solution introduces a deferred freeing mechanism for kernel page table pages, which provides a safe window to notify the IOMMU to invalidate its caches before the page is reused. This patch (of 8): In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware shares and walks the CPU's page tables. The x86 architecture maps the kernel's virtual address space into the upper portion of every process's page table. Consequently, in an SVA context, the IOMMU hardware can walk and cache kernel page table entries. The Linux kernel currently lacks a notification mechanism for kernel page table changes, specifically when page table pages are freed and reused. The IOMMU driver is only notified of changes to user virtual address mappings. This can cause the IOMMU's internal caches to retain stale entries for kernel VA. Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when kernel page table pages are freed and later reallocated. The IOMMU could misinterpret the new data as valid page table entries. The IOMMU might then walk into attacker-controlled memory, leading to arbitrary physical memory DMA access or privilege escalation. This is also a Write-After-Free issue, as the IOMMU will potentially continue to write Accessed and Dirty bits to the freed memory while attempting to walk the stale page tables. Currently, SVA contexts are unprivileged and cannot access kernel mappings. However, the IOMMU will still walk kernel-only page tables all the way down to the leaf entries, where it realizes the mapping is for the kernel and errors out. This means the IOMMU still caches these intermediate page table entries, making the described vulnerability a real concern. Disable SVA on x86 architecture until the IOMMU can receive notification to flush the paging cache before freeing the CPU kernel page table pages. Link: https://lkml.kernel.org/r/20251022082635.2462433-1-baolu.lu@linux.intel.com Link: https://lkml.kernel.org/r/20251022082635.2462433-2-baolu.lu@linux.intel.com Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices") Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Reviewed-by: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Betkov <bp(a)alien8.de> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jean-Philippe Brucker <jean-philippe(a)linaro.org> Cc: Joerg Roedel <joro(a)8bytes.org> Cc: Kevin Tian <kevin.tian(a)intel.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robin Murohy <robin.murphy(a)arm.com> Cc: Thomas Gleinxer <tglx(a)linutronix.de> Cc: "Uladzislau Rezki (Sony)" <urezki(a)gmail.com> Cc: Vasant Hegde <vasant.hegde(a)amd.com> Cc: Vinicius Costa Gomes <vinicius.gomes(a)intel.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Cc: Yi Lai <yi1.lai(a)intel.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 1a51cfd82808..a0442faad952 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -77,6 +77,9 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm if (!group) return ERR_PTR(-ENODEV); + if (IS_ENABLED(CONFIG_X86)) + return ERR_PTR(-EOPNOTSUPP); + mutex_lock(&iommu_sva_lock); /* Allocate mm->pasid if necessary. */

5 days

FAILED: patch "[PATCH] iommu: disable SVA when CONFIG_X86 is set" 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 72f98ef9a4be30d2a60136dd6faee376f780d06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010503-tweezers-junction-c503@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 72f98ef9a4be30d2a60136dd6faee376f780d06c Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Wed, 22 Oct 2025 16:26:27 +0800 Subject: [PATCH] iommu: disable SVA when CONFIG_X86 is set Patch series "Fix stale IOTLB entries for kernel address space", v7. This proposes a fix for a security vulnerability related to IOMMU Shared Virtual Addressing (SVA). In an SVA context, an IOMMU can cache kernel page table entries. When a kernel page table page is freed and reallocated for another purpose, the IOMMU might still hold stale, incorrect entries. This can be exploited to cause a use-after-free or write-after-free condition, potentially leading to privilege escalation or data corruption. This solution introduces a deferred freeing mechanism for kernel page table pages, which provides a safe window to notify the IOMMU to invalidate its caches before the page is reused. This patch (of 8): In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware shares and walks the CPU's page tables. The x86 architecture maps the kernel's virtual address space into the upper portion of every process's page table. Consequently, in an SVA context, the IOMMU hardware can walk and cache kernel page table entries. The Linux kernel currently lacks a notification mechanism for kernel page table changes, specifically when page table pages are freed and reused. The IOMMU driver is only notified of changes to user virtual address mappings. This can cause the IOMMU's internal caches to retain stale entries for kernel VA. Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when kernel page table pages are freed and later reallocated. The IOMMU could misinterpret the new data as valid page table entries. The IOMMU might then walk into attacker-controlled memory, leading to arbitrary physical memory DMA access or privilege escalation. This is also a Write-After-Free issue, as the IOMMU will potentially continue to write Accessed and Dirty bits to the freed memory while attempting to walk the stale page tables. Currently, SVA contexts are unprivileged and cannot access kernel mappings. However, the IOMMU will still walk kernel-only page tables all the way down to the leaf entries, where it realizes the mapping is for the kernel and errors out. This means the IOMMU still caches these intermediate page table entries, making the described vulnerability a real concern. Disable SVA on x86 architecture until the IOMMU can receive notification to flush the paging cache before freeing the CPU kernel page table pages. Link: https://lkml.kernel.org/r/20251022082635.2462433-1-baolu.lu@linux.intel.com Link: https://lkml.kernel.org/r/20251022082635.2462433-2-baolu.lu@linux.intel.com Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices") Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Reviewed-by: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Betkov <bp(a)alien8.de> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jean-Philippe Brucker <jean-philippe(a)linaro.org> Cc: Joerg Roedel <joro(a)8bytes.org> Cc: Kevin Tian <kevin.tian(a)intel.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robin Murohy <robin.murphy(a)arm.com> Cc: Thomas Gleinxer <tglx(a)linutronix.de> Cc: "Uladzislau Rezki (Sony)" <urezki(a)gmail.com> Cc: Vasant Hegde <vasant.hegde(a)amd.com> Cc: Vinicius Costa Gomes <vinicius.gomes(a)intel.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Cc: Yi Lai <yi1.lai(a)intel.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 1a51cfd82808..a0442faad952 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -77,6 +77,9 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm if (!group) return ERR_PTR(-ENODEV); + if (IS_ENABLED(CONFIG_X86)) + return ERR_PTR(-EOPNOTSUPP); + mutex_lock(&iommu_sva_lock); /* Allocate mm->pasid if necessary. */

5 days

FAILED: patch "[PATCH] iommu: disable SVA when CONFIG_X86 is set" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 72f98ef9a4be30d2a60136dd6faee376f780d06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010501-uninvited-verbose-d23b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 72f98ef9a4be30d2a60136dd6faee376f780d06c Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Wed, 22 Oct 2025 16:26:27 +0800 Subject: [PATCH] iommu: disable SVA when CONFIG_X86 is set Patch series "Fix stale IOTLB entries for kernel address space", v7. This proposes a fix for a security vulnerability related to IOMMU Shared Virtual Addressing (SVA). In an SVA context, an IOMMU can cache kernel page table entries. When a kernel page table page is freed and reallocated for another purpose, the IOMMU might still hold stale, incorrect entries. This can be exploited to cause a use-after-free or write-after-free condition, potentially leading to privilege escalation or data corruption. This solution introduces a deferred freeing mechanism for kernel page table pages, which provides a safe window to notify the IOMMU to invalidate its caches before the page is reused. This patch (of 8): In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware shares and walks the CPU's page tables. The x86 architecture maps the kernel's virtual address space into the upper portion of every process's page table. Consequently, in an SVA context, the IOMMU hardware can walk and cache kernel page table entries. The Linux kernel currently lacks a notification mechanism for kernel page table changes, specifically when page table pages are freed and reused. The IOMMU driver is only notified of changes to user virtual address mappings. This can cause the IOMMU's internal caches to retain stale entries for kernel VA. Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when kernel page table pages are freed and later reallocated. The IOMMU could misinterpret the new data as valid page table entries. The IOMMU might then walk into attacker-controlled memory, leading to arbitrary physical memory DMA access or privilege escalation. This is also a Write-After-Free issue, as the IOMMU will potentially continue to write Accessed and Dirty bits to the freed memory while attempting to walk the stale page tables. Currently, SVA contexts are unprivileged and cannot access kernel mappings. However, the IOMMU will still walk kernel-only page tables all the way down to the leaf entries, where it realizes the mapping is for the kernel and errors out. This means the IOMMU still caches these intermediate page table entries, making the described vulnerability a real concern. Disable SVA on x86 architecture until the IOMMU can receive notification to flush the paging cache before freeing the CPU kernel page table pages. Link: https://lkml.kernel.org/r/20251022082635.2462433-1-baolu.lu@linux.intel.com Link: https://lkml.kernel.org/r/20251022082635.2462433-2-baolu.lu@linux.intel.com Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices") Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Reviewed-by: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Betkov <bp(a)alien8.de> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jean-Philippe Brucker <jean-philippe(a)linaro.org> Cc: Joerg Roedel <joro(a)8bytes.org> Cc: Kevin Tian <kevin.tian(a)intel.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robin Murohy <robin.murphy(a)arm.com> Cc: Thomas Gleinxer <tglx(a)linutronix.de> Cc: "Uladzislau Rezki (Sony)" <urezki(a)gmail.com> Cc: Vasant Hegde <vasant.hegde(a)amd.com> Cc: Vinicius Costa Gomes <vinicius.gomes(a)intel.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Cc: Yi Lai <yi1.lai(a)intel.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 1a51cfd82808..a0442faad952 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -77,6 +77,9 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm if (!group) return ERR_PTR(-ENODEV); + if (IS_ENABLED(CONFIG_X86)) + return ERR_PTR(-EOPNOTSUPP); + mutex_lock(&iommu_sva_lock); /* Allocate mm->pasid if necessary. */

5 days

FAILED: patch "[PATCH] iommu/tegra: fix device leak on probe_device()" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

5 days

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