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FAILED: patch "[PATCH] btrfs: ensure no dirty metadata is written back for an fs" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 2618849f31e7cf51fadd4a5242458501a6d5b315 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025110858-banker-discolor-266d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2618849f31e7cf51fadd4a5242458501a6d5b315 Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 23 Oct 2025 19:44:04 +1030 Subject: [PATCH] btrfs: ensure no dirty metadata is written back for an fs with errors [BUG] During development of a minor feature (make sure all btrfs_bio::end_io() is called in task context), I noticed a crash in generic/388, where metadata writes triggered new works after btrfs_stop_all_workers(). It turns out that it can even happen without any code modification, just using RAID5 for metadata and the same workload from generic/388 is going to trigger the use-after-free. [CAUSE] If btrfs hits an error, the fs is marked as error, no new transaction is allowed thus metadata is in a frozen state. But there are some metadata modifications before that error, and they are still in the btree inode page cache. Since there will be no real transaction commit, all those dirty folios are just kept as is in the page cache, and they can not be invalidated by invalidate_inode_pages2() call inside close_ctree(), because they are dirty. And finally after btrfs_stop_all_workers(), we call iput() on btree inode, which triggers writeback of those dirty metadata. And if the fs is using RAID56 metadata, this will trigger RMW and queue new works into rmw_workers, which is already stopped, causing warning from queue_work() and use-after-free. [FIX] Add a special handling for write_one_eb(), that if the fs is already in an error state, immediately mark the bbio as failure, instead of really submitting them. Then during close_ctree(), iput() will just discard all those dirty tree blocks without really writing them back, thus no more new jobs for already stopped-and-freed workqueues. The extra discard in write_one_eb() also acts as an extra safenet. E.g. the transaction abort is triggered by some extent/free space tree corruptions, and since extent/free space tree is already corrupted some tree blocks may be allocated where they shouldn't be (overwriting existing tree blocks). In that case writing them back will further corrupting the fs. CC: stable(a)vger.kernel.org # 6.6+ Reviewed-by: Filipe Manana <fdmanana(a)suse.com> Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 755ec6dfd51c..23273d0e6f22 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2228,6 +2228,14 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb, wbc_account_cgroup_owner(wbc, folio, range_len); folio_unlock(folio); } + /* + * If the fs is already in error status, do not submit any writeback + * but immediately finish it. + */ + if (unlikely(BTRFS_FS_ERROR(fs_info))) { + btrfs_bio_end_io(bbio, errno_to_blk_status(BTRFS_FS_ERROR(fs_info))); + return; + } btrfs_submit_bbio(bbio, 0); }

2 weeks, 6 days

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FAILED: patch "[PATCH] drm/mediatek: Disable AFBC support on Mediatek DRM driver" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 9882a40640036d5bbc590426a78981526d4f2345 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025110838-imply-extruding-3561@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9882a40640036d5bbc590426a78981526d4f2345 Mon Sep 17 00:00:00 2001 From: Ariel D'Alessandro <ariel.dalessandro(a)collabora.com> Date: Fri, 24 Oct 2025 17:27:56 -0300 Subject: [PATCH] drm/mediatek: Disable AFBC support on Mediatek DRM driver Commit c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM driver") added AFBC support to Mediatek DRM and enabled the 32x8/split/sparse modifier. However, this is currently broken on Mediatek MT8188 (Genio 700 EVK platform); tested using upstream Kernel and Mesa (v25.2.1), AFBC is used by default since Mesa v25.0. Kernel trace reports vblank timeouts constantly, and the render is garbled: ``` [CRTC:62:crtc-0] vblank wait timed out WARNING: CPU: 7 PID: 70 at drivers/gpu/drm/drm_atomic_helper.c:1835 drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c [...] Hardware name: MediaTek Genio-700 EVK (DT) Workqueue: events_unbound commit_work pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c lr : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c sp : ffff80008337bca0 x29: ffff80008337bcd0 x28: 0000000000000061 x27: 0000000000000000 x26: 0000000000000001 x25: 0000000000000000 x24: ffff0000c9dcc000 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c66f2f80 x20: ffff0000c0d7d880 x19: 0000000000000000 x18: 000000000000000a x17: 000000040044ffff x16: 005000f2b5503510 x15: 0000000000000000 x14: 0000000000000000 x13: 74756f2064656d69 x12: 742074696177206b x11: 0000000000000058 x10: 0000000000000018 x9 : ffff800082396a70 x8 : 0000000000057fa8 x7 : 0000000000000cce x6 : ffff8000823eea70 x5 : ffff0001fef5f408 x4 : ffff80017ccee000 x3 : ffff0000c12cb480 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c12cb480 Call trace: drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c (P) drm_atomic_helper_commit_tail_rpm+0x64/0x80 commit_tail+0xa4/0x1a4 commit_work+0x14/0x20 process_one_work+0x150/0x290 worker_thread+0x2d0/0x3ec kthread+0x12c/0x210 ret_from_fork+0x10/0x20 ---[ end trace 0000000000000000 ]--- ``` Until this gets fixed upstream, disable AFBC support on this platform, as it's currently broken with upstream Mesa. Fixes: c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM driver") Cc: stable(a)vger.kernel.org Signed-off-by: Ariel D'Alessandro <ariel.dalessandro(a)collabora.com> Reviewed-by: Daniel Stone <daniels(a)collabora.com> Reviewed-by: CK Hu <ck.hu(a)mediatek.com> Reviewed-by: Macpaul Lin <macpaul.lin(a)mediatek.com> Link: https://patchwork.kernel.org/project/dri-devel/patch/20251024202756.811425-… Signed-off-by: Chun-Kuang Hu <chunkuang.hu(a)kernel.org> diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediatek/mtk_plane.c index 02349bd44001..788b52c1d10c 100644 --- a/drivers/gpu/drm/mediatek/mtk_plane.c +++ b/drivers/gpu/drm/mediatek/mtk_plane.c @@ -21,9 +21,6 @@ static const u64 modifiers[] = { DRM_FORMAT_MOD_LINEAR, - DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 | - AFBC_FORMAT_MOD_SPLIT | - AFBC_FORMAT_MOD_SPARSE), DRM_FORMAT_MOD_INVALID, }; @@ -71,26 +68,7 @@ static bool mtk_plane_format_mod_supported(struct drm_plane *plane, uint32_t format, uint64_t modifier) { - if (modifier == DRM_FORMAT_MOD_LINEAR) - return true; - - if (modifier != DRM_FORMAT_MOD_ARM_AFBC( - AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 | - AFBC_FORMAT_MOD_SPLIT | - AFBC_FORMAT_MOD_SPARSE)) - return false; - - if (format != DRM_FORMAT_XRGB8888 && - format != DRM_FORMAT_ARGB8888 && - format != DRM_FORMAT_BGRX8888 && - format != DRM_FORMAT_BGRA8888 && - format != DRM_FORMAT_ABGR8888 && - format != DRM_FORMAT_XBGR8888 && - format != DRM_FORMAT_RGB888 && - format != DRM_FORMAT_BGR888) - return false; - - return true; + return modifier == DRM_FORMAT_MOD_LINEAR; } static void mtk_plane_destroy_state(struct drm_plane *plane,

2 weeks, 6 days

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[PATCH] ksmbd: vfs: fix truncate lock-range check for shrink/grow and avoid size==0 underflow

by Qianchang Zhao

ksmbd_vfs_truncate() uses check_lock_range() with arguments that are incorrect for shrink, and can underflow when size==0: - For shrink, the code passed [inode->i_size, size-1], which is reversed. - When size==0, "size-1" underflows to -1, so the range becomes [old_size, -1], effectively skipping the intended [0, old_size-1]. Fix by: - Rejecting negative size with -EINVAL. - For shrink (size < old): check [size, old-1]. - For grow (size > old): check [old, size-1]. - Skip lock check when size == old. - Keep the return value on conflict as -EAGAIN (no noisy pr_err()). This avoids the size==0 underflow and uses the correct range order, preserving byte-range lock semantics. Reported-by: Qianchang Zhao <pioooooooooip(a)gmail.com> Reported-by: Zhitong Liu <liuzhitong1993(a)gmail.com> Cc: stable(a)vger.kernel.org Signed-off-by: Qianchang Zhao <pioooooooooip(a)gmail.com> --- fs/smb/server/vfs.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 891ed2dc2..e7843ec9b 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -825,17 +825,27 @@ int ksmbd_vfs_truncate(struct ksmbd_work *work, if (!work->tcon->posix_extensions) { struct inode *inode = file_inode(filp); - if (size < inode->i_size) { - err = check_lock_range(filp, size, - inode->i_size - 1, WRITE); - } else { - err = check_lock_range(filp, inode->i_size, - size - 1, WRITE); + loff_t old = i_size_read(inode); + loff_t start = 0, end = -1; + bool need_check = false; + + if (size < 0) + return -EINVAL; + + if (size < old) { + start = size; + end = old - 1; + need_check = true; + } else if (size > old) { + start = old; + end = size - 1; + need_check = true; } - if (err) { - pr_err("failed due to lock\n"); - return -EAGAIN; + if (need_check) { + err = check_lock_range(filp, start, end, WRITE); + if (err) + return -EAGAIN; } } -- 2.34.1

2 weeks, 6 days

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[PATCH v6 1/2] dt-bindings: media: qcom,qcs8300-camss: Add missing power supplies

by Vikram Sharma

Add missing vdda-phy-supply and vdda-pll-supply in the (monaco)qcs8300 camss binding. While enabling imx412 sensor for qcs8300 we see a need to add these supplies which were missing in initial submission. Fixes: 634a2958fae30 ("media: dt-bindings: Add qcom,qcs8300-camss compatible") Cc: <stable(a)vger.kernel.org> Co-developed-by: Nihal Kumar Gupta <quic_nihalkum(a)quicinc.com> Signed-off-by: Nihal Kumar Gupta <quic_nihalkum(a)quicinc.com> Signed-off-by: Vikram Sharma <quic_vikramsa(a)quicinc.com> --- .../bindings/media/qcom,qcs8300-camss.yaml | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/Documentation/devicetree/bindings/media/qcom,qcs8300-camss.yaml b/Documentation/devicetree/bindings/media/qcom,qcs8300-camss.yaml index 80a4540a22dc..e5f170aa4d9e 100644 --- a/Documentation/devicetree/bindings/media/qcom,qcs8300-camss.yaml +++ b/Documentation/devicetree/bindings/media/qcom,qcs8300-camss.yaml @@ -120,6 +120,14 @@ properties: items: - const: top + vdda-phy-supply: + description: + Phandle to a 0.88V regulator supply to CSI PHYs. + + vdda-pll-supply: + description: + Phandle to 1.2V regulator supply to CSI PHYs pll block. + ports: $ref: /schemas/graph.yaml#/properties/ports @@ -160,6 +168,8 @@ required: - power-domains - power-domain-names - ports + - vdda-phy-supply + - vdda-pll-supply additionalProperties: false @@ -328,6 +338,9 @@ examples: power-domains = <&camcc CAM_CC_TITAN_TOP_GDSC>; power-domain-names = "top"; + vdda-phy-supply = <&vreg_l4a_0p88>; + vdda-pll-supply = <&vreg_l1c_1p2>; + ports { #address-cells = <1>; #size-cells = <0>; -- 2.34.1

3 weeks

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[PATCH 5/6] KVM: SVM: Add missing save/restore handling of LBR MSRs

by Yosry Ahmed

MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So save/restore is completely broken. Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to LBR MSRs from userspace only (as they are read-only MSRs). Additionally, to correctly restore L1's LBRs while L2 is running, make sure the LBRs are copied from the captured VMCB01 save area in svm_copy_vmrun_state(). Fixes: 24e09cbf480a ("KVM: SVM: enable LBR virtualization") Cc: stable(a)vger.kernel.org Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> --- arch/x86/kvm/svm/nested.c | 3 +++ arch/x86/kvm/svm/svm.c | 20 ++++++++++++++++++++ arch/x86/kvm/x86.c | 3 +++ 3 files changed, 26 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index e7861392f2fcd..955de5d90f48e 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1057,6 +1057,9 @@ void svm_copy_vmrun_state(struct vmcb_save_area *to_save, to_save->isst_addr = from_save->isst_addr; to_save->ssp = from_save->ssp; } + + if (lbrv) + svm_copy_lbrs(to_save, from_save); } void svm_copy_vmloadsave_state(struct vmcb *to_vmcb, struct vmcb *from_vmcb) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9eb112f0e61f0..45faf892a0431 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2988,6 +2988,26 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) vmcb_mark_dirty(svm->vmcb, VMCB_LBR); svm_update_lbrv(vcpu); break; + case MSR_IA32_LASTBRANCHFROMIP: + if (!msr->host_initiated) + return 1; + svm->vmcb->save.br_from = data; + break; + case MSR_IA32_LASTBRANCHTOIP: + if (!msr->host_initiated) + return 1; + svm->vmcb->save.br_to = data; + break; + case MSR_IA32_LASTINTFROMIP: + if (!msr->host_initiated) + return 1; + svm->vmcb->save.last_excp_from = data; + break; + case MSR_IA32_LASTINTTOIP: + if (!msr->host_initiated) + return 1; + svm->vmcb->save.last_excp_to = data; + break; case MSR_VM_HSAVE_PA: /* * Old kernels did not validate the value written to diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9c2e28028c2b5..1d36a0f782c49 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -348,6 +348,9 @@ static const u32 msrs_to_save_base[] = { MSR_IA32_U_CET, MSR_IA32_S_CET, MSR_IA32_PL0_SSP, MSR_IA32_PL1_SSP, MSR_IA32_PL2_SSP, MSR_IA32_PL3_SSP, MSR_IA32_INT_SSP_TAB, + MSR_IA32_DEBUGCTLMSR, + MSR_IA32_LASTBRANCHFROMIP, MSR_IA32_LASTBRANCHTOIP, + MSR_IA32_LASTINTFROMIP, MSR_IA32_LASTINTTOIP, }; static const u32 msrs_to_save_pmu[] = { -- 2.51.2.1041.gc1ab5b90ca-goog

3 weeks

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[PATCH 1/1] firmware: stratix10-svc: stop kernel thread once service is completed

by Khairul A. Romli

From: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> This patch resolves a customer-reported issue where the Stratix10 SVC service layer caused maximum CPU utilization. The original logic only stopped the thread if it was running and there was one or fewer active clients. This overly restrictive condition prevented the thread from stopping even when the application was active, leading to unnecessary CPU consumption. The updated logic now stops the thread whenever it is running, regardless of the number of active clients, ensuring better resource management and resolving the performance issue. Fixes: 7ca5ce896524 ("firmware: add Intel Stratix10 service layer driver") Cc: stable(a)vger.kernel.org # 5.4+ Signed-off-by: Richard Gong <richard.gong(a)intel.com> Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> --- drivers/firmware/stratix10-svc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c index e3f990d888d7..ec39522711ea 100644 --- a/drivers/firmware/stratix10-svc.c +++ b/drivers/firmware/stratix10-svc.c @@ -1040,8 +1040,8 @@ EXPORT_SYMBOL_GPL(stratix10_svc_send); */ void stratix10_svc_done(struct stratix10_svc_chan *chan) { - /* stop thread when thread is running AND only one active client */ - if (chan->ctrl->task && chan->ctrl->num_active_client <= 1) { + /* stop thread when thread is running */ + if (chan->ctrl->task) { pr_debug("svc_smc_hvc_shm_thread is stopped\n"); kthread_stop(chan->ctrl->task); chan->ctrl->task = NULL; -- 2.43.7

3 weeks

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[PATCH] rust: kbuild: skip gendwarfksyms in `bindings.o` for Rust >= 1.91.0

by Miguel Ojeda

Starting with Rust 1.91.0 (released 2025-10-30), in upstream commit ab91a63d403b ("Ignore intrinsic calls in cross-crate-inlining cost model") [1][2], `bindings.o` stops containing DWARF debug information because the `Default` implementations contained `write_bytes()` calls which are now ignored in that cost model (note that `CLIPPY=1` does not reproduce it). This means `gendwarfksyms` complains: RUSTC L rust/bindings.o error: gendwarfksyms: process_module: dwarf_get_units failed: no debugging information? For the moment, conditionally skip `gendwarfksyms` for Rust >= 1.91.0. Cc: stable(a)vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Reported-by: Haiyue Wang <haiyuewa(a)163.com> Closes: https://lore.kernel.org/rust-for-linux/b8c1c73d-bf8b-4bf2-beb1-84ffdcd60547… Link: https://github.com/rust-lang/rust/commit/ab91a63d403b0105cacd72809cd292a729… [1] Link: https://github.com/rust-lang/rust/pull/145910 [2] Signed-off-by: Miguel Ojeda <ojeda(a)kernel.org> --- rust/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/rust/Makefile b/rust/Makefile index 3e545c1a0ff4..269bf7cf5b97 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -543,6 +543,7 @@ $(obj)/ffi.o: private skip_gendwarfksyms = 1 $(obj)/ffi.o: $(src)/ffi.rs $(obj)/compiler_builtins.o FORCE +$(call if_changed_rule,rustc_library) +$(obj)/bindings.o: private skip_gendwarfksyms := $(if $(call rustc-min-version,109100),1) $(obj)/bindings.o: private rustc_target_flags = --extern ffi --extern pin_init $(obj)/bindings.o: $(src)/bindings/lib.rs \ $(obj)/ffi.o \ base-commit: dc77806cf3b4788d328fddf245e86c5b529f31a2 -- 2.51.2

3 weeks

3
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[PATCH net v2] strparser: Fix signed/unsigned mismatch bug

by Nate Karstens

The `len` member of the sk_buff is an unsigned int. This is cast to `ssize_t` (a signed type) for the first sk_buff in the comparison, but not the second sk_buff. On 32-bit systems, this can result in an integer underflow for certain values because unsigned arithmetic is being used. This appears to be an oversight: if the intention was to use unsigned arithmetic, then the first cast would have been omitted. The change ensures both len values are cast to `ssize_t`. The underflow causes an issue with ktls when multiple TLS PDUs are included in a single TCP segment. The mainline kernel does not use strparser for ktls anymore, but this is still useful for other features that still use strparser, and for backporting. Signed-off-by: Nate Karstens <nate.karstens(a)garmin.com> Cc: stable(a)vger.kernel.org Fixes: 43a0c6751a32 ("strparser: Stream parser for messages") --- net/strparser/strparser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index 43b1f558b33d..e659fea2da70 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -238,7 +238,7 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, strp_parser_err(strp, -EMSGSIZE, desc); break; } else if (len <= (ssize_t)head->len - - skb->len - stm->strp.offset) { + (ssize_t)skb->len - stm->strp.offset) { /* Length must be into new skb (and also * greater than zero) */ -- 2.34.1

3 weeks

4
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[PATCH] fsi: Fix device refcount leak in i2cr_scom_probe

by Ma Ke

This patch fixes a device reference count leak in the i2cr_scom driver by adding proper put_device() calls in both error paths and the remove function. Found by code review. Cc: stable(a)vger.kernel.org Fixes: c0b34bed0bbf ("fsi: Add I2C Responder SCOM driver") Signed-off-by: Ma Ke <make24(a)iscas.ac.cn> --- drivers/fsi/i2cr-scom.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/fsi/i2cr-scom.c b/drivers/fsi/i2cr-scom.c index cb7e02213032..11506d321d7e 100644 --- a/drivers/fsi/i2cr-scom.c +++ b/drivers/fsi/i2cr-scom.c @@ -104,14 +104,20 @@ static int i2cr_scom_probe(struct device *dev) ret = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx); if (ret) - return ret; + goto err_put_device; dev_set_name(&scom->dev, "scom%d", didx); cdev_init(&scom->cdev, &i2cr_scom_fops); ret = cdev_device_add(&scom->cdev, &scom->dev); if (ret) - fsi_free_minor(scom->dev.devt); + goto err_free_minor; + + return ret; +err_free_minor: + fsi_free_minor(scom->dev.devt); +err_put_device: + put_device(&scom->dev); return ret; } -- 2.17.1

3 weeks

3
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[PATCH 3/6] KVM: nSVM: Fix and simplify LBR virtualization handling with nested

by Yosry Ahmed

The current scheme for handling LBRV when nested is used is very complicated, especially when L1 does not enable LBRV (i.e. does not set LBR_CTL_ENABLE_MASK). To avoid copying LBRs between VMCB01 and VMCB02 on every nested transition, the current implementation switches between using VMCB01 or VMCB02 as the source of truth for the LBRs while L2 is running. If L2 enables LBR, VMCB02 is used as the source of truth. When L2 disables LBR, the LBRs are copied to VMCB01 and VMCB01 is used as the source of truth. This introduces significant complexity, and incorrect behavior in some cases. For example, on a nested #VMEXIT, the LBRs are only copied from VMCB02 to VMCB01 if LBRV is enabled in VMCB01. This is because L2's writes to MSR_IA32_DEBUGCTLMSR to enable LBR are intercepted and propagated to VMCB01 instead of VMCB02. However, LBRV is only enabled in VMCB02 when L2 is running. This means that if L2 enables LBR and exits to L1, the LBRs will not be propagated from VMCB02 to VMCB01, because LBRV is disabled in VMCB01. There is no meaningful difference in CPUID rate in L2 when copying LBRs on every nested transition vs. the current approach, so do the simple and correct thing and always copy LBRs between VMCB01 and VMCB02 on nested transitions (when LBRV is disabled by L1). Drop the conditional LBRs copying in __svm_{enable/disable}_lbrv() as it is now unnecessary. VMCB02 becomes the only source of truth for LBRs when L2 is running, regardless of LBRV being enabled by L1, drop svm_get_lbr_vmcb() and use svm->vmcb directly in its place. Fixes: 1d5a1b5860ed ("KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running") Cc: stable(a)vger.kernel.org Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> --- arch/x86/kvm/svm/nested.c | 20 ++++++----------- arch/x86/kvm/svm/svm.c | 46 +++++++++------------------------------ 2 files changed, 17 insertions(+), 49 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 71664d54d8b2a..c81005b245222 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -678,11 +678,10 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 */ svm_copy_lbrs(vmcb02, vmcb12); vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS; - svm_update_lbrv(&svm->vcpu); - - } else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) { + } else { svm_copy_lbrs(vmcb02, vmcb01); } + svm_update_lbrv(&svm->vcpu); } static inline bool is_evtinj_soft(u32 evtinj) @@ -835,11 +834,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm, svm->soft_int_next_rip = vmcb12_rip; } - vmcb02->control.virt_ext = vmcb01->control.virt_ext & - LBR_CTL_ENABLE_MASK; - if (guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV)) - vmcb02->control.virt_ext |= - (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK); + /* LBR_CTL_ENABLE_MASK is controlled by svm_update_lbrv() */ if (!nested_vmcb_needs_vls_intercept(svm)) vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK; @@ -1191,13 +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->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) svm_copy_lbrs(vmcb12, vmcb02); - svm_update_lbrv(vcpu); - } else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) { + else svm_copy_lbrs(vmcb01, vmcb02); - svm_update_lbrv(vcpu); - } + + svm_update_lbrv(vcpu); if (vnmi) { if (vmcb02->control.int_ctl & V_NMI_BLOCKING_MASK) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 26ab75ecf1c67..fc42bcdbb5200 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -808,13 +808,7 @@ void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb) static void __svm_enable_lbrv(struct kvm_vcpu *vcpu) { - struct vcpu_svm *svm = to_svm(vcpu); - - svm->vmcb->control.virt_ext |= LBR_CTL_ENABLE_MASK; - - /* Move the LBR msrs to the vmcb02 so that the guest can see them. */ - if (is_guest_mode(vcpu)) - svm_copy_lbrs(svm->vmcb, svm->vmcb01.ptr); + to_svm(vcpu)->vmcb->control.virt_ext |= LBR_CTL_ENABLE_MASK; } void svm_enable_lbrv(struct kvm_vcpu *vcpu) @@ -825,35 +819,15 @@ void svm_enable_lbrv(struct kvm_vcpu *vcpu) static void __svm_disable_lbrv(struct kvm_vcpu *vcpu) { - struct vcpu_svm *svm = to_svm(vcpu); - KVM_BUG_ON(sev_es_guest(vcpu->kvm), vcpu->kvm); - svm->vmcb->control.virt_ext &= ~LBR_CTL_ENABLE_MASK; - - /* - * Move the LBR msrs back to the vmcb01 to avoid copying them - * on nested guest entries. - */ - if (is_guest_mode(vcpu)) - svm_copy_lbrs(svm->vmcb01.ptr, svm->vmcb); -} - -static struct vmcb *svm_get_lbr_vmcb(struct vcpu_svm *svm) -{ - /* - * If LBR virtualization is disabled, the LBR MSRs are always kept in - * vmcb01. If LBR virtualization is enabled and L1 is running VMs of - * its own, the MSRs are moved between vmcb01 and vmcb02 as needed. - */ - return svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK ? svm->vmcb : - svm->vmcb01.ptr; + to_svm(vcpu)->vmcb->control.virt_ext &= ~LBR_CTL_ENABLE_MASK; } void svm_update_lbrv(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); bool current_enable_lbrv = svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK; - bool enable_lbrv = (svm_get_lbr_vmcb(svm)->save.dbgctl & DEBUGCTLMSR_LBR) || + bool enable_lbrv = (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) || (is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK)); @@ -2738,19 +2712,19 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) msr_info->data = svm->tsc_aux; break; case MSR_IA32_DEBUGCTLMSR: - msr_info->data = svm_get_lbr_vmcb(svm)->save.dbgctl; + msr_info->data = svm->vmcb->save.dbgctl; break; case MSR_IA32_LASTBRANCHFROMIP: - msr_info->data = svm_get_lbr_vmcb(svm)->save.br_from; + msr_info->data = svm->vmcb->save.br_from; break; case MSR_IA32_LASTBRANCHTOIP: - msr_info->data = svm_get_lbr_vmcb(svm)->save.br_to; + msr_info->data = svm->vmcb->save.br_to; break; case MSR_IA32_LASTINTFROMIP: - msr_info->data = svm_get_lbr_vmcb(svm)->save.last_excp_from; + msr_info->data = svm->vmcb->save.last_excp_from; break; case MSR_IA32_LASTINTTOIP: - msr_info->data = svm_get_lbr_vmcb(svm)->save.last_excp_to; + msr_info->data = svm->vmcb->save.last_excp_to; break; case MSR_VM_HSAVE_PA: msr_info->data = svm->nested.hsave_msr; @@ -3018,10 +2992,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) if (data & DEBUGCTL_RESERVED_BITS) return 1; - if (svm_get_lbr_vmcb(svm)->save.dbgctl == data) + if (svm->vmcb->save.dbgctl == data) break; - svm_get_lbr_vmcb(svm)->save.dbgctl = data; + svm->vmcb->save.dbgctl = data; vmcb_mark_dirty(svm->vmcb, VMCB_LBR); svm_update_lbrv(vcpu); break; -- 2.51.2.1041.gc1ab5b90ca-goog

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