December 2024 - Linux-stable-mirror

FAILED: patch "[PATCH] ksmbd: fix Out-of-Bounds Read in ksmbd_vfs_stream_read" 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 fc342cf86e2dc4d2edb0fc2ff5e28b6c7845adb9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121056-come-ultimatum-bead@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fc342cf86e2dc4d2edb0fc2ff5e28b6c7845adb9 Mon Sep 17 00:00:00 2001 From: Jordy Zomer <jordyzomer(a)google.com> Date: Thu, 28 Nov 2024 09:32:45 +0900 Subject: [PATCH] ksmbd: fix Out-of-Bounds Read in ksmbd_vfs_stream_read An offset from client could be a negative value, It could lead to an out-of-bounds read from the stream_buf. Note that this issue is coming when setting 'vfs objects = streams_xattr parameter' in ksmbd.conf. Cc: stable(a)vger.kernel.org # v5.15+ Reported-by: Jordy Zomer <jordyzomer(a)google.com> Signed-off-by: Jordy Zomer <jordyzomer(a)google.com> Signed-off-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 416f7df4edef..7b6a3952f228 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -6663,6 +6663,10 @@ int smb2_read(struct ksmbd_work *work) } offset = le64_to_cpu(req->Offset); + if (offset < 0) { + err = -EINVAL; + goto out; + } length = le32_to_cpu(req->Length); mincount = le32_to_cpu(req->MinimumCount);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121041-chewing-fondly-715d@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" 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 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121040-shank-cod-65b4@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" 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 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121039-gout-trillion-3df8@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" 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 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121038-anytime-depraved-896a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" 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 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121037-coveted-divinely-7c35@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-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-6.12.y git checkout FETCH_HEAD git cherry-pick -x 7f71507851fc7764b36a3221839607d3a45c2025 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024121035-showplace-revision-773b@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f71507851fc7764b36a3221839607d3a45c2025 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhuacai(a)kernel.org> Date: Tue, 3 Dec 2024 19:49:28 +0800 Subject: [PATCH] LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCU When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable(a)vger.kernel.org Reviewed-by: Bibo Mao <maobibo(a)loongson.cn> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index 69f3e3782cc9..a7893bd01e73 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -156,7 +156,7 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst) int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; unsigned long *val; u32 addr, rd, rj, opcode; @@ -167,7 +167,6 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) rj = inst.reg2_format.rj; opcode = inst.reg2_format.opcode; addr = vcpu->arch.gprs[rj]; - ret = EMULATE_DO_IOCSR; run->iocsr_io.phys_addr = addr; run->iocsr_io.is_write = 0; val = &vcpu->arch.gprs[rd]; @@ -207,20 +206,28 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu) } if (run->iocsr_io.is_write) { - if (!kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save data and let user space to write it */ memcpy(run->iocsr_io.data, val, run->iocsr_io.len); - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val); } else { - if (!kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val)) + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + if (ret == 0) ret = EMULATE_DONE; - else + else { + ret = EMULATE_DO_IOCSR; /* Save register id for iocsr read completion */ vcpu->arch.io_gpr = rd; - + } trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL); } @@ -359,7 +366,7 @@ static int kvm_handle_gspr(struct kvm_vcpu *vcpu) int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int op8, opcode, rd; struct kvm_run *run = vcpu->run; @@ -464,8 +471,10 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, &vcpu->arch.gprs[rd]); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) { update_pc(&vcpu->arch); vcpu->mmio_needed = 0; @@ -531,7 +540,7 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run) int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) { - int ret; + int idx, ret; unsigned int rd, op8, opcode; unsigned long curr_pc, rd_val = 0; struct kvm_run *run = vcpu->run; @@ -631,7 +640,9 @@ int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst) * it need not return to user space to handle the mmio * exception. */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, vcpu->arch.badv, run->mmio.len, data); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!ret) return EMULATE_DONE; diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c index a233a323e295..93f4acd44523 100644 --- a/arch/loongarch/kvm/intc/ipi.c +++ b/arch/loongarch/kvm/intc/ipi.c @@ -98,7 +98,7 @@ static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) { - int i, ret; + int i, idx, ret; uint32_t val = 0, mask = 0; /* @@ -107,7 +107,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) */ if ((data >> 27) & 0xf) { /* Read the old val */ + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) { kvm_err("%s: : read date from addr %llx failed\n", __func__, addr); return ret; @@ -121,7 +123,9 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data) val &= mask; } val |= ((uint32_t)(data >> 32) & ~mask); + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val); + srcu_read_unlock(&vcpu->kvm->srcu, idx); if (unlikely(ret)) kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);

9 months

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FAILED: patch "[PATCH] mm: page_alloc: move mlocked flag clearance into" 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 66edc3a5894c74f8887c8af23b97593a0dd0df4d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111714-varsity-grub-d888@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 66edc3a5894c74f8887c8af23b97593a0dd0df4d Mon Sep 17 00:00:00 2001 From: Roman Gushchin <roman.gushchin(a)linux.dev> Date: Wed, 6 Nov 2024 19:53:54 +0000 Subject: [PATCH] mm: page_alloc: move mlocked flag clearance into free_pages_prepare() Syzbot reported a bad page state problem caused by a page being freed using free_page() still having a mlocked flag at free_pages_prepare() stage: BUG: Bad page state in process syz.5.504 pfn:61f45 page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61f45 flags: 0xfff00000080204(referenced|workingset|mlocked|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000080204 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), pid 8443, tgid 8442 (syz.5.504), ts 201884660643, free_ts 201499827394 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537 prep_new_page mm/page_alloc.c:1545 [inline] get_page_from_freelist+0x303f/0x3190 mm/page_alloc.c:3457 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4733 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 kvm_coalesced_mmio_init+0x1f/0xf0 virt/kvm/coalesced_mmio.c:99 kvm_create_vm virt/kvm/kvm_main.c:1235 [inline] kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5488 [inline] kvm_dev_ioctl+0x12dc/0x2240 virt/kvm/kvm_main.c:5530 __do_compat_sys_ioctl fs/ioctl.c:1007 [inline] __se_compat_sys_ioctl+0x510/0xc90 fs/ioctl.c:950 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386 do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e page last free pid 8399 tgid 8399 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_folios+0xf12/0x18d0 mm/page_alloc.c:2686 folios_put_refs+0x76c/0x860 mm/swap.c:1007 free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:335 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline] tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:366 [inline] tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465 exit_mmap+0x496/0xc40 mm/mmap.c:1926 __mmput+0x115/0x390 kernel/fork.c:1348 exit_mm+0x220/0x310 kernel/exit.c:571 do_exit+0x9b2/0x28e0 kernel/exit.c:926 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Modules linked in: CPU: 0 UID: 0 PID: 8442 Comm: syz.5.504 Not tainted 6.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 bad_page+0x176/0x1d0 mm/page_alloc.c:501 free_page_is_bad mm/page_alloc.c:918 [inline] free_pages_prepare mm/page_alloc.c:1100 [inline] free_unref_page+0xed0/0xf20 mm/page_alloc.c:2638 kvm_destroy_vm virt/kvm/kvm_main.c:1327 [inline] kvm_put_kvm+0xc75/0x1350 virt/kvm/kvm_main.c:1386 kvm_vcpu_release+0x54/0x60 virt/kvm/kvm_main.c:4143 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:939 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __ia32_sys_exit_group+0x3f/0x40 kernel/exit.c:1097 ia32_sys_call+0x2624/0x2630 arch/x86/include/generated/asm/syscalls_32.h:253 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386 do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf745d579 Code: Unable to access opcode bytes at 0xf745d54f. RSP: 002b:00000000f75afd6c EFLAGS: 00000206 ORIG_RAX: 00000000000000fc RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000ffffff9c RDI: 00000000f744cff4 RBP: 00000000f717ae61 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> The problem was originally introduced by commit b109b87050df ("mm/munlock: replace clear_page_mlock() by final clearance"): it was focused on handling pagecache and anonymous memory and wasn't suitable for lower level get_page()/free_page() API's used for example by KVM, as with this reproducer. Fix it by moving the mlocked flag clearance down to free_page_prepare(). The bug itself if fairly old and harmless (aside from generating these warnings), aside from a small memory leak - "bad" pages are stopped from being allocated again. Link: https://lkml.kernel.org/r/20241106195354.270757-1-roman.gushchin@linux.dev Fixes: b109b87050df ("mm/munlock: replace clear_page_mlock() by final clearance") Signed-off-by: Roman Gushchin <roman.gushchin(a)linux.dev> Reported-by: syzbot+e985d3026c4fd041578e(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/6729f475.050a0220.701a.0019.GAE@google.com Acked-by: Hugh Dickins <hughd(a)google.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Sean Christopherson <seanjc(a)google.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c6c7bb3ea71b..216fbbfbedcf 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1048,6 +1048,7 @@ __always_inline bool free_pages_prepare(struct page *page, bool skip_kasan_poison = should_skip_kasan_poison(page); bool init = want_init_on_free(); bool compound = PageCompound(page); + struct folio *folio = page_folio(page); VM_BUG_ON_PAGE(PageTail(page), page); @@ -1057,6 +1058,20 @@ __always_inline bool free_pages_prepare(struct page *page, if (memcg_kmem_online() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); + /* + * In rare cases, when truncation or holepunching raced with + * munlock after VM_LOCKED was cleared, Mlocked may still be + * found set here. This does not indicate a problem, unless + * "unevictable_pgs_cleared" appears worryingly large. + */ + if (unlikely(folio_test_mlocked(folio))) { + long nr_pages = folio_nr_pages(folio); + + __folio_clear_mlocked(folio); + zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages); + count_vm_events(UNEVICTABLE_PGCLEARED, nr_pages); + } + if (unlikely(PageHWPoison(page)) && !order) { /* Do not let hwpoison pages hit pcplists/buddy */ reset_page_owner(page, order); diff --git a/mm/swap.c b/mm/swap.c index b8e3259ea2c4..59f30a981c6f 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -78,20 +78,6 @@ static void __page_cache_release(struct folio *folio, struct lruvec **lruvecp, lruvec_del_folio(*lruvecp, folio); __folio_clear_lru_flags(folio); } - - /* - * In rare cases, when truncation or holepunching raced with - * munlock after VM_LOCKED was cleared, Mlocked may still be - * found set here. This does not indicate a problem, unless - * "unevictable_pgs_cleared" appears worryingly large. - */ - if (unlikely(folio_test_mlocked(folio))) { - long nr_pages = folio_nr_pages(folio); - - __folio_clear_mlocked(folio); - zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages); - count_vm_events(UNEVICTABLE_PGCLEARED, nr_pages); - } } /*

9 months

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Apply 60fc1e675013 to 6.12.y

by Miguel Ojeda

Hi Greg, Sasha, Please consider applying commit 60fc1e675013 ("rust: allow `clippy::needless_lifetimes`") to 6.12.y. It is meant to avoid Clippy warnings with Rust 1.83.0 (released two weeks ago), since 6.12 LTS is the first stable kernel that supports a minimum Rust version, thus users may use newer compilers. Older LTSs do not need it, for that reason. It applies cleanly. Thanks! Cheers, Miguel

9 months

2
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[PATCH] fs/ceph/mds_client: give up on paths longer than PATH_MAX

by Max Kellermann

If the full path to be built by ceph_mdsc_build_path() happens to be longer than PATH_MAX, then this function will enter an endless (retry) loop, effectively blocking the whole task. Most of the machine becomes unusable, making this a very simple and effective DoS vulnerability. I cannot imagine why this retry was ever implemented, but it seems rather useless and harmful to me. Let's remove it and fail with ENAMETOOLONG instead. Cc: stable(a)vger.kernel.org Reported-by: Dario Weißer <dario(a)cure53.de> Signed-off-by: Max Kellermann <max.kellermann(a)ionos.com> --- fs/ceph/mds_client.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index c4a5fd94bbbb..4f6ac015edcd 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -2808,12 +2808,11 @@ char *ceph_mdsc_build_path(struct ceph_mds_client *mdsc, struct dentry *dentry, if (pos < 0) { /* - * A rename didn't occur, but somehow we didn't end up where - * we thought we would. Throw a warning and try again. + * The path is longer than PATH_MAX and this function + * cannot ever succeed. Creating paths that long is + * possible with Ceph, but Linux cannot use them. */ - pr_warn_client(cl, "did not end path lookup where expected (pos = %d)\n", - pos); - goto retry; + return ERR_PTR(-ENAMETOOLONG); } *pbase = base; -- 2.45.2

9 months

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