January 2022 - Linux-stable-mirror

FAILED: patch "[PATCH] perf: Protect perf_guest_cbs with RCU" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ff083a2d972f56bebfd82409ca62e5dfce950961 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Thu, 11 Nov 2021 02:07:22 +0000 Subject: [PATCH] perf: Protect perf_guest_cbs with RCU Protect perf_guest_cbs with RCU to fix multiple possible errors. Luckily, all paths that read perf_guest_cbs already require RCU protection, e.g. to protect the callback chains, so only the direct perf_guest_cbs touchpoints need to be modified. Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure perf_guest_cbs isn't reloaded between a !NULL check and a dereference. Fixed via the READ_ONCE() in rcu_dereference(). Bug #2 is that on weakly-ordered architectures, updates to the callbacks themselves are not guaranteed to be visible before the pointer is made visible to readers. Fixed by the smp_store_release() in rcu_assign_pointer() when the new pointer is non-NULL. Bug #3 is that, because the callbacks are global, it's possible for readers to run in parallel with an unregisters, and thus a module implementing the callbacks can be unloaded while readers are in flight, resulting in a use-after-free. Fixed by a synchronize_rcu() call when unregistering callbacks. Bug #1 escaped notice because it's extremely unlikely a compiler will reload perf_guest_cbs in this sequence. perf_guest_cbs does get reloaded for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest() guard all but guarantees the consumer will win the race, e.g. to nullify perf_guest_cbs, KVM has to completely exit the guest and teardown down all VMs before KVM start its module unload / unregister sequence. This also makes it all but impossible to encounter bug #3. Bug #2 has not been a problem because all architectures that register callbacks are strongly ordered and/or have a static set of callbacks. But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming kvm_intel module load/unload leads to: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:perf_misc_flags+0x1c/0x70 Call Trace: perf_prepare_sample+0x53/0x6b0 perf_event_output_forward+0x67/0x160 __perf_event_overflow+0x52/0xf0 handle_pmi_common+0x207/0x300 intel_pmu_handle_irq+0xcf/0x410 perf_event_nmi_handler+0x28/0x50 nmi_handle+0xc7/0x260 default_do_nmi+0x6b/0x170 exc_nmi+0x103/0x130 asm_exc_nmi+0x76/0xbf Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host") Signed-off-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Reviewed-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c index 3b69a76d341e..1626dfc6f6ce 100644 --- a/arch/arm/kernel/perf_callchain.c +++ b/arch/arm/kernel/perf_callchain.c @@ -62,9 +62,10 @@ user_backtrace(struct frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct frame_tail __user *tail; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -98,9 +99,10 @@ callchain_trace(struct stackframe *fr, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -111,18 +113,21 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 4a72c2727309..86d9f2013172 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -102,7 +102,9 @@ compat_user_backtrace(struct compat_frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -147,9 +149,10 @@ static bool callchain_trace(void *data, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe frame; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -160,18 +163,21 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c index ab55e98ee8f6..35318a635a5f 100644 --- a/arch/csky/kernel/perf_callchain.c +++ b/arch/csky/kernel/perf_callchain.c @@ -86,10 +86,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->regs[4]; @@ -110,10 +111,11 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("C-SKY does not support perf in guest mode!"); return; } diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c index 0ce6f9f307e6..f38791960781 100644 --- a/arch/nds32/kernel/perf_event_cpu.c +++ b/arch/nds32/kernel/perf_event_cpu.c @@ -1363,6 +1363,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; unsigned long gp = 0; unsigned long lp = 0; @@ -1371,7 +1372,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, leaf_fp = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1479,9 +1480,10 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1493,20 +1495,23 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c index 0bb1854dce83..8ecfc4c128bc 100644 --- a/arch/riscv/kernel/perf_callchain.c +++ b/arch/riscv/kernel/perf_callchain.c @@ -56,10 +56,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->s0; @@ -78,8 +79,10 @@ static bool fill_callchain(void *entry, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("RISC-V does not support perf in guest mode!"); return; } diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 38b2c779146f..32cec290d3ad 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2768,10 +2768,11 @@ static bool perf_hw_regs(struct pt_regs *regs) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct unwind_state state; unsigned long addr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2871,10 +2872,11 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *ent void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stack_frame frame; const struct stack_frame __user *fp; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2951,18 +2953,21 @@ static unsigned long code_segment_base(struct pt_regs *regs) unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return regs->ip + code_segment_base(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 42cf01ecdd13..2258e02ca350 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2837,6 +2837,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) { struct perf_sample_data data; struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + struct perf_guest_info_callbacks *guest_cbs; int bit; int handled = 0; u64 intel_ctrl = hybrid(cpuc->pmu, intel_ctrl); @@ -2903,9 +2904,11 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) */ if (__test_and_clear_bit(GLOBAL_STATUS_TRACE_TOPAPMI_BIT, (unsigned long *)&status)) { handled++; - if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && - perf_guest_cbs->handle_intel_pt_intr)) - perf_guest_cbs->handle_intel_pt_intr(); + + guest_cbs = perf_get_guest_cbs(); + if (unlikely(guest_cbs && guest_cbs->is_in_guest() && + guest_cbs->handle_intel_pt_intr)) + guest_cbs->handle_intel_pt_intr(); else intel_pt_interrupt(); } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0dcfd265beed..318c489b735b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1240,7 +1240,18 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags); -extern struct perf_guest_info_callbacks *perf_guest_cbs; +extern struct perf_guest_info_callbacks __rcu *perf_guest_cbs; +static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) +{ + /* + * Callbacks are RCU-protected and must be READ_ONCE to avoid reloading + * the callbacks between a !NULL check and dereferences, to ensure + * pending stores/changes to the callback pointers are visible before a + * non-NULL perf_guest_cbs is visible to readers, and to prevent a + * module from unloading callbacks while readers are active. + */ + return rcu_dereference(perf_guest_cbs); +} extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); diff --git a/kernel/events/core.c b/kernel/events/core.c index 523106a506ee..c552e1bfcaea 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6526,18 +6526,25 @@ static void perf_pending_event(struct irq_work *entry) * Later on, we might change it to a list if there is * another virtualization implementation supporting the callbacks. */ -struct perf_guest_info_callbacks *perf_guest_cbs; +struct perf_guest_info_callbacks __rcu *perf_guest_cbs; int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = cbs; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) + return -EBUSY; + + rcu_assign_pointer(perf_guest_cbs, cbs); return 0; } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = NULL; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) + return -EINVAL; + + rcu_assign_pointer(perf_guest_cbs, NULL); + synchronize_rcu(); return 0; } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

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FAILED: patch "[PATCH] perf: Protect perf_guest_cbs with RCU" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ff083a2d972f56bebfd82409ca62e5dfce950961 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Thu, 11 Nov 2021 02:07:22 +0000 Subject: [PATCH] perf: Protect perf_guest_cbs with RCU Protect perf_guest_cbs with RCU to fix multiple possible errors. Luckily, all paths that read perf_guest_cbs already require RCU protection, e.g. to protect the callback chains, so only the direct perf_guest_cbs touchpoints need to be modified. Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure perf_guest_cbs isn't reloaded between a !NULL check and a dereference. Fixed via the READ_ONCE() in rcu_dereference(). Bug #2 is that on weakly-ordered architectures, updates to the callbacks themselves are not guaranteed to be visible before the pointer is made visible to readers. Fixed by the smp_store_release() in rcu_assign_pointer() when the new pointer is non-NULL. Bug #3 is that, because the callbacks are global, it's possible for readers to run in parallel with an unregisters, and thus a module implementing the callbacks can be unloaded while readers are in flight, resulting in a use-after-free. Fixed by a synchronize_rcu() call when unregistering callbacks. Bug #1 escaped notice because it's extremely unlikely a compiler will reload perf_guest_cbs in this sequence. perf_guest_cbs does get reloaded for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest() guard all but guarantees the consumer will win the race, e.g. to nullify perf_guest_cbs, KVM has to completely exit the guest and teardown down all VMs before KVM start its module unload / unregister sequence. This also makes it all but impossible to encounter bug #3. Bug #2 has not been a problem because all architectures that register callbacks are strongly ordered and/or have a static set of callbacks. But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming kvm_intel module load/unload leads to: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:perf_misc_flags+0x1c/0x70 Call Trace: perf_prepare_sample+0x53/0x6b0 perf_event_output_forward+0x67/0x160 __perf_event_overflow+0x52/0xf0 handle_pmi_common+0x207/0x300 intel_pmu_handle_irq+0xcf/0x410 perf_event_nmi_handler+0x28/0x50 nmi_handle+0xc7/0x260 default_do_nmi+0x6b/0x170 exc_nmi+0x103/0x130 asm_exc_nmi+0x76/0xbf Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host") Signed-off-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Reviewed-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c index 3b69a76d341e..1626dfc6f6ce 100644 --- a/arch/arm/kernel/perf_callchain.c +++ b/arch/arm/kernel/perf_callchain.c @@ -62,9 +62,10 @@ user_backtrace(struct frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct frame_tail __user *tail; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -98,9 +99,10 @@ callchain_trace(struct stackframe *fr, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -111,18 +113,21 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 4a72c2727309..86d9f2013172 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -102,7 +102,9 @@ compat_user_backtrace(struct compat_frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -147,9 +149,10 @@ static bool callchain_trace(void *data, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe frame; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -160,18 +163,21 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c index ab55e98ee8f6..35318a635a5f 100644 --- a/arch/csky/kernel/perf_callchain.c +++ b/arch/csky/kernel/perf_callchain.c @@ -86,10 +86,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->regs[4]; @@ -110,10 +111,11 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("C-SKY does not support perf in guest mode!"); return; } diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c index 0ce6f9f307e6..f38791960781 100644 --- a/arch/nds32/kernel/perf_event_cpu.c +++ b/arch/nds32/kernel/perf_event_cpu.c @@ -1363,6 +1363,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; unsigned long gp = 0; unsigned long lp = 0; @@ -1371,7 +1372,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, leaf_fp = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1479,9 +1480,10 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1493,20 +1495,23 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c index 0bb1854dce83..8ecfc4c128bc 100644 --- a/arch/riscv/kernel/perf_callchain.c +++ b/arch/riscv/kernel/perf_callchain.c @@ -56,10 +56,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->s0; @@ -78,8 +79,10 @@ static bool fill_callchain(void *entry, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("RISC-V does not support perf in guest mode!"); return; } diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 38b2c779146f..32cec290d3ad 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2768,10 +2768,11 @@ static bool perf_hw_regs(struct pt_regs *regs) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct unwind_state state; unsigned long addr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2871,10 +2872,11 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *ent void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stack_frame frame; const struct stack_frame __user *fp; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2951,18 +2953,21 @@ static unsigned long code_segment_base(struct pt_regs *regs) unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return regs->ip + code_segment_base(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 42cf01ecdd13..2258e02ca350 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2837,6 +2837,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) { struct perf_sample_data data; struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + struct perf_guest_info_callbacks *guest_cbs; int bit; int handled = 0; u64 intel_ctrl = hybrid(cpuc->pmu, intel_ctrl); @@ -2903,9 +2904,11 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) */ if (__test_and_clear_bit(GLOBAL_STATUS_TRACE_TOPAPMI_BIT, (unsigned long *)&status)) { handled++; - if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && - perf_guest_cbs->handle_intel_pt_intr)) - perf_guest_cbs->handle_intel_pt_intr(); + + guest_cbs = perf_get_guest_cbs(); + if (unlikely(guest_cbs && guest_cbs->is_in_guest() && + guest_cbs->handle_intel_pt_intr)) + guest_cbs->handle_intel_pt_intr(); else intel_pt_interrupt(); } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0dcfd265beed..318c489b735b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1240,7 +1240,18 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags); -extern struct perf_guest_info_callbacks *perf_guest_cbs; +extern struct perf_guest_info_callbacks __rcu *perf_guest_cbs; +static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) +{ + /* + * Callbacks are RCU-protected and must be READ_ONCE to avoid reloading + * the callbacks between a !NULL check and dereferences, to ensure + * pending stores/changes to the callback pointers are visible before a + * non-NULL perf_guest_cbs is visible to readers, and to prevent a + * module from unloading callbacks while readers are active. + */ + return rcu_dereference(perf_guest_cbs); +} extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); diff --git a/kernel/events/core.c b/kernel/events/core.c index 523106a506ee..c552e1bfcaea 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6526,18 +6526,25 @@ static void perf_pending_event(struct irq_work *entry) * Later on, we might change it to a list if there is * another virtualization implementation supporting the callbacks. */ -struct perf_guest_info_callbacks *perf_guest_cbs; +struct perf_guest_info_callbacks __rcu *perf_guest_cbs; int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = cbs; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) + return -EBUSY; + + rcu_assign_pointer(perf_guest_cbs, cbs); return 0; } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = NULL; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) + return -EINVAL; + + rcu_assign_pointer(perf_guest_cbs, NULL); + synchronize_rcu(); return 0; } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

2 years, 11 months

1
0
0 0

FAILED: patch "[PATCH] perf: Protect perf_guest_cbs with RCU" failed to apply to 4.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.4-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ff083a2d972f56bebfd82409ca62e5dfce950961 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Thu, 11 Nov 2021 02:07:22 +0000 Subject: [PATCH] perf: Protect perf_guest_cbs with RCU Protect perf_guest_cbs with RCU to fix multiple possible errors. Luckily, all paths that read perf_guest_cbs already require RCU protection, e.g. to protect the callback chains, so only the direct perf_guest_cbs touchpoints need to be modified. Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure perf_guest_cbs isn't reloaded between a !NULL check and a dereference. Fixed via the READ_ONCE() in rcu_dereference(). Bug #2 is that on weakly-ordered architectures, updates to the callbacks themselves are not guaranteed to be visible before the pointer is made visible to readers. Fixed by the smp_store_release() in rcu_assign_pointer() when the new pointer is non-NULL. Bug #3 is that, because the callbacks are global, it's possible for readers to run in parallel with an unregisters, and thus a module implementing the callbacks can be unloaded while readers are in flight, resulting in a use-after-free. Fixed by a synchronize_rcu() call when unregistering callbacks. Bug #1 escaped notice because it's extremely unlikely a compiler will reload perf_guest_cbs in this sequence. perf_guest_cbs does get reloaded for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest() guard all but guarantees the consumer will win the race, e.g. to nullify perf_guest_cbs, KVM has to completely exit the guest and teardown down all VMs before KVM start its module unload / unregister sequence. This also makes it all but impossible to encounter bug #3. Bug #2 has not been a problem because all architectures that register callbacks are strongly ordered and/or have a static set of callbacks. But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming kvm_intel module load/unload leads to: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:perf_misc_flags+0x1c/0x70 Call Trace: perf_prepare_sample+0x53/0x6b0 perf_event_output_forward+0x67/0x160 __perf_event_overflow+0x52/0xf0 handle_pmi_common+0x207/0x300 intel_pmu_handle_irq+0xcf/0x410 perf_event_nmi_handler+0x28/0x50 nmi_handle+0xc7/0x260 default_do_nmi+0x6b/0x170 exc_nmi+0x103/0x130 asm_exc_nmi+0x76/0xbf Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host") Signed-off-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Reviewed-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c index 3b69a76d341e..1626dfc6f6ce 100644 --- a/arch/arm/kernel/perf_callchain.c +++ b/arch/arm/kernel/perf_callchain.c @@ -62,9 +62,10 @@ user_backtrace(struct frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct frame_tail __user *tail; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -98,9 +99,10 @@ callchain_trace(struct stackframe *fr, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -111,18 +113,21 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 4a72c2727309..86d9f2013172 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -102,7 +102,9 @@ compat_user_backtrace(struct compat_frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -147,9 +149,10 @@ static bool callchain_trace(void *data, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe frame; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -160,18 +163,21 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c index ab55e98ee8f6..35318a635a5f 100644 --- a/arch/csky/kernel/perf_callchain.c +++ b/arch/csky/kernel/perf_callchain.c @@ -86,10 +86,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->regs[4]; @@ -110,10 +111,11 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("C-SKY does not support perf in guest mode!"); return; } diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c index 0ce6f9f307e6..f38791960781 100644 --- a/arch/nds32/kernel/perf_event_cpu.c +++ b/arch/nds32/kernel/perf_event_cpu.c @@ -1363,6 +1363,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; unsigned long gp = 0; unsigned long lp = 0; @@ -1371,7 +1372,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, leaf_fp = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1479,9 +1480,10 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } @@ -1493,20 +1495,23 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c index 0bb1854dce83..8ecfc4c128bc 100644 --- a/arch/riscv/kernel/perf_callchain.c +++ b/arch/riscv/kernel/perf_callchain.c @@ -56,10 +56,11 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (guest_cbs && guest_cbs->is_in_guest()) return; fp = regs->s0; @@ -78,8 +79,10 @@ static bool fill_callchain(void *entry, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { pr_warn("RISC-V does not support perf in guest mode!"); return; } diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 38b2c779146f..32cec290d3ad 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2768,10 +2768,11 @@ static bool perf_hw_regs(struct pt_regs *regs) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct unwind_state state; unsigned long addr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2871,10 +2872,11 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *ent void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stack_frame frame; const struct stack_frame __user *fp; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (guest_cbs && guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return; } @@ -2951,18 +2953,21 @@ static unsigned long code_segment_base(struct pt_regs *regs) unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); + + if (guest_cbs && guest_cbs->is_in_guest()) + return guest_cbs->get_guest_ip(); return regs->ip + code_segment_base(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { + struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest_cbs && guest_cbs->is_in_guest()) { + if (guest_cbs->is_user_mode()) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 42cf01ecdd13..2258e02ca350 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2837,6 +2837,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) { struct perf_sample_data data; struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + struct perf_guest_info_callbacks *guest_cbs; int bit; int handled = 0; u64 intel_ctrl = hybrid(cpuc->pmu, intel_ctrl); @@ -2903,9 +2904,11 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) */ if (__test_and_clear_bit(GLOBAL_STATUS_TRACE_TOPAPMI_BIT, (unsigned long *)&status)) { handled++; - if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && - perf_guest_cbs->handle_intel_pt_intr)) - perf_guest_cbs->handle_intel_pt_intr(); + + guest_cbs = perf_get_guest_cbs(); + if (unlikely(guest_cbs && guest_cbs->is_in_guest() && + guest_cbs->handle_intel_pt_intr)) + guest_cbs->handle_intel_pt_intr(); else intel_pt_interrupt(); } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0dcfd265beed..318c489b735b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1240,7 +1240,18 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags); -extern struct perf_guest_info_callbacks *perf_guest_cbs; +extern struct perf_guest_info_callbacks __rcu *perf_guest_cbs; +static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) +{ + /* + * Callbacks are RCU-protected and must be READ_ONCE to avoid reloading + * the callbacks between a !NULL check and dereferences, to ensure + * pending stores/changes to the callback pointers are visible before a + * non-NULL perf_guest_cbs is visible to readers, and to prevent a + * module from unloading callbacks while readers are active. + */ + return rcu_dereference(perf_guest_cbs); +} extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); diff --git a/kernel/events/core.c b/kernel/events/core.c index 523106a506ee..c552e1bfcaea 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6526,18 +6526,25 @@ static void perf_pending_event(struct irq_work *entry) * Later on, we might change it to a list if there is * another virtualization implementation supporting the callbacks. */ -struct perf_guest_info_callbacks *perf_guest_cbs; +struct perf_guest_info_callbacks __rcu *perf_guest_cbs; int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = cbs; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) + return -EBUSY; + + rcu_assign_pointer(perf_guest_cbs, cbs); return 0; } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { - perf_guest_cbs = NULL; + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) + return -EINVAL; + + rcu_assign_pointer(perf_guest_cbs, NULL); + synchronize_rcu(); return 0; } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

2 years, 11 months

1
0
0 0

[PATCH] efi: runtime: avoid EFIv2 runtime services on Apple x86 machines

by Ard Biesheuvel

Aditya reports [0] that his recent MacbookPro crashes in the firmware when using the variable services at runtime. The culprit appears to be a call to QueryVariableInfo(), which we did not use to call on Apple x86 machines in the past as they only upgraded from EFI v1.10 to EFI v2.40 firmware fairly recently, and QueryVariableInfo() (along with UpdateCapsule() et al) was added in EFI v2.00. The only runtime service introduced in EFI v2.00 that we actually use in Linux is QueryVariableInfo(), as the capsule based ones are optional, generally not used at runtime (all the LVFS/fwupd firmware update infrastructure uses helper EFI programs that invoke capsule update at boot time, not runtime), and not implemented by Apple machines in the first place. QueryVariableInfo() is used to 'safely' set variables, i.e., only when there is enough space. This prevents machines with buggy firmwares from corrupting their NVRAMs when they run out of space. Given that Apple machines have been using EFI v1.10 services only for the longest time (the EFI v2.0 spec was released in 2006, and Linux support for the newly introduced runtime services was added in 2011, but the MacbookPro12,1 released in 2015 still claims to be EFI v1.10 only), let's avoid the EFI v2.0 ones on all Apple x86 machines. [0] https://lore.kernel.org/all/6D757C75-65B1-468B-842D-10410081A8E4@live.com/ Cc: <stable(a)vger.kernel.org> Cc: Jeremy Kerr <jk(a)ozlabs.org> Cc: Matthew Garrett <mjg59(a)srcf.ucam.org> Reported-by: Aditya Garg <gargaditya08(a)live.com> Tested-by: Orlando Chamberlain <redecorating(a)protonmail.com> Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> --- drivers/firmware/efi/efi.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index ae79c3300129..7de3f5b6e8d0 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -722,6 +722,13 @@ void __init efi_systab_report_header(const efi_table_hdr_t *systab_hdr, systab_hdr->revision >> 16, systab_hdr->revision & 0xffff, vendor); + + if (IS_ENABLED(CONFIG_X86_64) && + systab_hdr->revision > EFI_1_10_SYSTEM_TABLE_REVISION && + !strcmp(vendor, "Apple")) { + pr_info("Apple Mac detected, using EFI v1.10 runtime services only\n"); + efi.runtime_version = EFI_1_10_SYSTEM_TABLE_REVISION; + } } static __initdata char memory_type_name[][13] = { -- 2.30.2

2 years, 11 months

2
2
0 0

[PATCH v2 1/1] psi: Fix uaf issue when psi trigger is destroyed while being polled

by Suren Baghdasaryan

With write operation on psi files replacing old trigger with a new one, the lifetime of its waitqueue is totally arbitrary. Overwriting an existing trigger causes its waitqueue to be freed and pending poll() will stumble on trigger->event_wait which was destroyed. Fix this by disallowing to redefine an existing psi trigger. If a write operation is used on a file descriptor with an already existing psi trigger, the operation will fail with EBUSY error. Also bypass a check for psi_disabled in the psi_trigger_destroy as the flag can be flipped after the trigger is created, leading to a memory leak. Fixes: 0e94682b73bf ("psi: introduce psi monitor") Cc: stable(a)vger.kernel.org Reported-by: syzbot+cdb5dd11c97cc532efad(a)syzkaller.appspotmail.com Analyzed-by: Eric Biggers <ebiggers(a)kernel.org> Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> --- Changes in v2: - Added Fixes tag, per Eric Biggers - CC'ed stable(a)vger.kernel.org, per Eric Biggers - Removed unnecessary READ_ONCE/WRITE_ONCE, per Eric Biggers - Changed psi_trigger_destroy to accept psi_trigger pointer, per Eric Biggers Documentation/accounting/psi.rst | 3 +- include/linux/psi.h | 2 +- include/linux/psi_types.h | 3 -- kernel/cgroup/cgroup.c | 11 ++++-- kernel/sched/psi.c | 66 ++++++++++++++------------------ 5 files changed, 40 insertions(+), 45 deletions(-) diff --git a/Documentation/accounting/psi.rst b/Documentation/accounting/psi.rst index f2b3439edcc2..860fe651d645 100644 --- a/Documentation/accounting/psi.rst +++ b/Documentation/accounting/psi.rst @@ -92,7 +92,8 @@ Triggers can be set on more than one psi metric and more than one trigger for the same psi metric can be specified. However for each trigger a separate file descriptor is required to be able to poll it separately from others, therefore for each trigger a separate open() syscall should be made even -when opening the same psi interface file. +when opening the same psi interface file. Write operations to a file descriptor +with an already existing psi trigger will fail with EBUSY. Monitors activate only when system enters stall state for the monitored psi metric and deactivates upon exit from the stall state. While system is diff --git a/include/linux/psi.h b/include/linux/psi.h index 65eb1476ac70..74f7148dfb9f 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -32,7 +32,7 @@ void cgroup_move_task(struct task_struct *p, struct css_set *to); struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, size_t nbytes, enum psi_res res); -void psi_trigger_replace(void **trigger_ptr, struct psi_trigger *t); +void psi_trigger_destroy(struct psi_trigger *t); __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, poll_table *wait); diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index 0a23300d49af..6537d0c92825 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -129,9 +129,6 @@ struct psi_trigger { * events to one per window */ u64 last_event_time; - - /* Refcounting to prevent premature destruction */ - struct kref refcount; }; struct psi_group { diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index cafb8c114a21..93b51a2104f7 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3642,6 +3642,12 @@ static ssize_t cgroup_pressure_write(struct kernfs_open_file *of, char *buf, cgroup_get(cgrp); cgroup_kn_unlock(of->kn); + /* Allow only one trigger per file descriptor */ + if (ctx->psi.trigger) { + cgroup_put(cgrp); + return -EBUSY; + } + psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi; new = psi_trigger_create(psi, buf, nbytes, res); if (IS_ERR(new)) { @@ -3649,8 +3655,7 @@ static ssize_t cgroup_pressure_write(struct kernfs_open_file *of, char *buf, return PTR_ERR(new); } - psi_trigger_replace(&ctx->psi.trigger, new); - + ctx->psi.trigger = new; cgroup_put(cgrp); return nbytes; @@ -3689,7 +3694,7 @@ static void cgroup_pressure_release(struct kernfs_open_file *of) { struct cgroup_file_ctx *ctx = of->priv; - psi_trigger_replace(&ctx->psi.trigger, NULL); + psi_trigger_destroy(ctx->psi.trigger); } bool cgroup_psi_enabled(void) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 1652f2bb54b7..1fe4b8d3ae98 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1151,7 +1151,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, t->event = 0; t->last_event_time = 0; init_waitqueue_head(&t->event_wait); - kref_init(&t->refcount); mutex_lock(&group->trigger_lock); @@ -1180,15 +1179,19 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, return t; } -static void psi_trigger_destroy(struct kref *ref) +void psi_trigger_destroy(struct psi_trigger *t) { - struct psi_trigger *t = container_of(ref, struct psi_trigger, refcount); - struct psi_group *group = t->group; + struct psi_group *group; struct task_struct *task_to_destroy = NULL; - if (static_branch_likely(&psi_disabled)) + /* + * We do not check psi_disabled since it might have been disabled after + * the trigger got created. + */ + if (!t) return; + group = t->group; /* * Wakeup waiters to stop polling. Can happen if cgroup is deleted * from under a polling process. @@ -1224,9 +1227,9 @@ static void psi_trigger_destroy(struct kref *ref) mutex_unlock(&group->trigger_lock); /* - * Wait for both *trigger_ptr from psi_trigger_replace and - * poll_task RCUs to complete their read-side critical sections - * before destroying the trigger and optionally the poll_task + * Wait for psi_schedule_poll_work RCU to complete its read-side + * critical section before destroying the trigger and optionally the + * poll_task. */ synchronize_rcu(); /* @@ -1243,18 +1246,6 @@ static void psi_trigger_destroy(struct kref *ref) kfree(t); } -void psi_trigger_replace(void **trigger_ptr, struct psi_trigger *new) -{ - struct psi_trigger *old = *trigger_ptr; - - if (static_branch_likely(&psi_disabled)) - return; - - rcu_assign_pointer(*trigger_ptr, new); - if (old) - kref_put(&old->refcount, psi_trigger_destroy); -} - __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, poll_table *wait) { @@ -1264,24 +1255,15 @@ __poll_t psi_trigger_poll(void **trigger_ptr, if (static_branch_likely(&psi_disabled)) return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI; - rcu_read_lock(); - - t = rcu_dereference(*(void __rcu __force **)trigger_ptr); - if (!t) { - rcu_read_unlock(); + t = READ_ONCE(*trigger_ptr); + if (!t) return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI; - } - kref_get(&t->refcount); - - rcu_read_unlock(); poll_wait(file, &t->event_wait, wait); if (cmpxchg(&t->event, 1, 0) == 1) ret |= EPOLLPRI; - kref_put(&t->refcount, psi_trigger_destroy); - return ret; } @@ -1305,14 +1287,24 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf, buf[buf_size - 1] = '\0'; - new = psi_trigger_create(&psi_system, buf, nbytes, res); - if (IS_ERR(new)) - return PTR_ERR(new); - seq = file->private_data; + /* Take seq->lock to protect seq->private from concurrent writes */ mutex_lock(&seq->lock); - psi_trigger_replace(&seq->private, new); + + /* Allow only one trigger per file descriptor */ + if (seq->private) { + mutex_unlock(&seq->lock); + return -EBUSY; + } + + new = psi_trigger_create(&psi_system, buf, nbytes, res); + if (IS_ERR(new)) { + mutex_unlock(&seq->lock); + return PTR_ERR(new); + } + + seq->private = new; mutex_unlock(&seq->lock); return nbytes; @@ -1347,7 +1339,7 @@ static int psi_fop_release(struct inode *inode, struct file *file) { struct seq_file *seq = file->private_data; - psi_trigger_replace(&seq->private, NULL); + psi_trigger_destroy(seq->private); return single_release(inode, file); } -- 2.34.1.575.g55b058a8bb-goog

2 years, 11 months

6
11
0 0

[PATCH] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

by Roberto Sassu

If virtio_gpu_object_shmem_init() fails (e.g. due to fault injection, as it happened in the bug report by syzbot), virtio_gpu_array_put_free() could be called with objs equal to NULL. Ensure that objs is not NULL in virtio_gpu_array_put_free(), or otherwise return from the function. Cc: stable(a)vger.kernel.org # 5.13.x Signed-off-by: Roberto Sassu <roberto.sassu(a)huawei.com> Reported-by: syzbot+e9072e90624a31dfa85f(a)syzkaller.appspotmail.com Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock virtio_gpu_object_array") --- drivers/gpu/drm/virtio/virtgpu_gem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c index 2de61b63ef91..48d3c9955f0d 100644 --- a/drivers/gpu/drm/virtio/virtgpu_gem.c +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c @@ -248,6 +248,9 @@ void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs) { u32 i; + if (!objs) + return; + for (i = 0; i < objs->nents; i++) drm_gem_object_put(objs->objs[i]); virtio_gpu_array_free(objs); -- 2.32.0

2 years, 11 months

2
2
0 0

[PATCH v3] xhci: re-initialize the HC during resume if HCE was set

by Puma Hsu

When HCE(Host Controller Error) is set, it means an internal error condition has been detected. It needs to re-initialize the HC too. Cc: stable(a)vger.kernel.org Signed-off-by: Puma Hsu <pumahsu(a)google.com> --- v2: Follow Sergey Shtylyov <s.shtylyov(a)omp.ru>'s comment. v3: Add stable(a)vger.kernel.org for stable release. drivers/usb/host/xhci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index dc357cabb265..ab440ce8420f 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1146,8 +1146,8 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) temp = readl(&xhci->op_regs->status); } - /* If restore operation fails, re-initialize the HC during resume */ - if ((temp & STS_SRE) || hibernated) { + /* If restore operation fails or HC error is detected, re-initialize the HC during resume */ + if ((temp & (STS_SRE | STS_HCE)) || hibernated) { if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) && !(xhci_all_ports_seen_u0(xhci))) { -- 2.34.1.448.ga2b2bfdf31-goog

2 years, 11 months

3
6
0 0

UBSAN error on is_dsc_supported

by Limonciello, Mario

[Public] Hi stable, Can you please pull in commit 63ad5371cd1e379519395c49a4b6a652c36c98e5 ("drm/amd/display: explicitly set is_dsc_supported to false before use") to 5.15.y? This fixes address sanitizer errors on hotplug found by the Canonical team. Thanks,

2 years, 11 months

2
1
0 0

[PATCH AUTOSEL 4.9 01/33] Bluetooth: Fix debugfs entry leak in hci_register_dev()

by Sasha Levin

From: Wei Yongjun <weiyongjun1(a)huawei.com> [ Upstream commit 5a4bb6a8e981d3d0d492aa38412ee80b21033177 ] Fault injection test report debugfs entry leak as follows: debugfs: Directory 'hci0' with parent 'bluetooth' already present! When register_pm_notifier() failed in hci_register_dev(), the debugfs create by debugfs_create_dir() do not removed in the error handing path. Add the remove debugfs code to fix it. Signed-off-by: Wei Yongjun <weiyongjun1(a)huawei.com> Signed-off-by: Marcel Holtmann <marcel(a)holtmann.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- net/bluetooth/hci_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index b43f31203a430..40e6e5feb1e06 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3148,6 +3148,7 @@ int hci_register_dev(struct hci_dev *hdev) return id; err_wqueue: + debugfs_remove_recursive(hdev->debugfs); destroy_workqueue(hdev->workqueue); destroy_workqueue(hdev->req_workqueue); err: -- 2.34.1

2 years, 11 months

1
10
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[PATCH AUTOSEL 4.14 01/56] Bluetooth: Fix debugfs entry leak in hci_register_dev()

by Sasha Levin

From: Wei Yongjun <weiyongjun1(a)huawei.com> [ Upstream commit 5a4bb6a8e981d3d0d492aa38412ee80b21033177 ] Fault injection test report debugfs entry leak as follows: debugfs: Directory 'hci0' with parent 'bluetooth' already present! When register_pm_notifier() failed in hci_register_dev(), the debugfs create by debugfs_create_dir() do not removed in the error handing path. Add the remove debugfs code to fix it. Signed-off-by: Wei Yongjun <weiyongjun1(a)huawei.com> Signed-off-by: Marcel Holtmann <marcel(a)holtmann.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- net/bluetooth/hci_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 1906adfd553ad..687b4d0e4c673 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3183,6 +3183,7 @@ int hci_register_dev(struct hci_dev *hdev) return id; err_wqueue: + debugfs_remove_recursive(hdev->debugfs); destroy_workqueue(hdev->workqueue); destroy_workqueue(hdev->req_workqueue); err: -- 2.34.1

2 years, 11 months

1
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Linux-stable-mirror January 2022