- 04 Aug, 2023 3 commits
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Paolo Bonzini authored
To avoid possible time-of-check/time-of-use issues, the GHCB should almost never be accessed outside dump_ghcb, sev_es_sync_to_ghcb and sev_es_sync_from_ghcb. The only legitimate uses are to set the exitinfo fields and to find the address of the scratch area embedded in the ghcb. Accessing ghcb_usage also goes through svm->sev_es.ghcb in sev_es_validate_vmgexit(), but that is because anyway the value is not used. Removing a shortcut variable that contains the value of svm->sev_es.ghcb makes these cases a bit more verbose, but it limits the chance of someone reading the ghcb by mistake. Signed-off-by:Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini authored
A KVM guest using SEV-ES or SEV-SNP with multiple vCPUs can trigger a double fetch race condition vulnerability and invoke the VMGEXIT handler recursively. sev_handle_vmgexit() maps the GHCB page using kvm_vcpu_map() and then fetches the exit code using ghcb_get_sw_exit_code(). Soon after, sev_es_validate_vmgexit() fetches the exit code again. Since the GHCB page is shared with the guest, the guest is able to quickly swap the values with another vCPU and hence bypass the validation. One vmexit code that can be rejected by sev_es_validate_vmgexit() is SVM_EXIT_VMGEXIT; if sev_handle_vmgexit() observes it in the second fetch, the call to svm_invoke_exit_handler() will invoke sev_handle_vmgexit() again recursively. To avoid the race, always fetch the GHCB data from the places where sev_es_sync_from_ghcb stores it. Exploiting recursions on linux kernel has been proven feasible in the past, but the impact is mitigated by stack guard pages (CONFIG_VMAP_STACK). Still, if an attacker manages to call the handler multiple times, they can theoretically trigger a stack overflow and cause a denial-of-service, or potentially guest-to-host escape in kernel configurations without stack guard pages. Note that winning the race reliably in every iteration is very tricky due to the very tight window of the fetches; depending on the compiler settings, they are often consecutive because of optimization and inlining. Tested by booting an SEV-ES RHEL9 guest. Fixes: CVE-2023-4155 Fixes: 291bd20d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT") Cc: stable@vger.kernel.org Reported-by:
Andy Nguyen <theflow@google.com> Signed-off-by:
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Paolo Bonzini authored
Validation of the GHCB is susceptible to time-of-check/time-of-use vulnerabilities. To avoid them, we would like to always snapshot the fields that are read in sev_es_validate_vmgexit(), and not use the GHCB anymore after it returns. This means: - invoking sev_es_sync_from_ghcb() before any GHCB access, including before sev_es_validate_vmgexit() - snapshotting all fields including the valid bitmap and the sw_scratch field, which are currently not caching anywhere. The valid bitmap is the first thing to be copied out of the GHCB; then, further accesses will use the copy in svm->sev_es. Fixes: 291bd20d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT") Cc: stable@vger.kernel.org Signed-off-by:
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- 29 Jul, 2023 21 commits
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Sean Christopherson authored
Add coverage to x86's set_sregs_test to verify KVM rejects vendor-agnostic illegal CR0 values, i.e. CR0 values whose legality doesn't depend on the current VMX mode. KVM historically has neglected to reject bad CR0s from userspace, i.e. would happily accept a completely bogus CR0 via KVM_SET_SREGS{2}. Punt VMX specific subtests to future work, as they would require quite a bit more effort, and KVM gets coverage for CR0 checks in general through other means, e.g. KVM-Unit-Tests. Signed-off-by:Sean Christopherson <seanjc@google.com> Message-Id: <20230613203037.1968489-4-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Stuff CR0 and/or CR4 to be compliant with a restricted guest if and only if KVM itself is not configured to utilize unrestricted guests, i.e. don't stuff CR0/CR4 for a restricted L2 that is running as the guest of an unrestricted L1. Any attempt to VM-Enter a restricted guest with invalid CR0/CR4 values should fail, i.e. in a nested scenario, KVM (as L0) should never observe a restricted L2 with incompatible CR0/CR4, since nested VM-Enter from L1 should have failed. And if KVM does observe an active, restricted L2 with incompatible state, e.g. due to a KVM bug, fudging CR0/CR4 instead of letting VM-Enter fail does more harm than good, as KVM will often neglect to undo the side effects, e.g. won't clear rmode.vm86_active on nested VM-Exit, and thus the damage can easily spill over to L1. On the other hand, letting VM-Enter fail due to bad guest state is more likely to contain the damage to L2 as KVM relies on hardware to perform most guest state consistency checks, i.e. KVM needs to be able to reflect a failed nested VM-Enter into L1 irrespective of (un)restricted guest behavior. Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Fixes: bddd82d1 ("KVM: nVMX: KVM needs to unset "unrestricted guest" VM-execution control in vmcs02 if vmcs12 doesn't set it") Signed-off-by:
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Sean Christopherson authored
Reject KVM_SET_SREGS{2} with -EINVAL if the incoming CR0 is invalid, e.g. due to setting bits 63:32, illegal combinations, or to a value that isn't allowed in VMX (non-)root mode. The VMX checks in particular are "fun" as failure to disallow Real Mode for an L2 that is configured with unrestricted guest disabled, when KVM itself has unrestricted guest enabled, will result in KVM forcing VM86 mode to virtual Real Mode for L2, but then fail to unwind the related metadata when synthesizing a nested VM-Exit back to L1 (which has unrestricted guest enabled). Opportunistically fix a benign typo in the prototype for is_valid_cr4(). Cc: stable@vger.kernel.org Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000f316b705fdf6e2b4@google.comSigned-off-by: -
Sean Christopherson authored
Remove coccinelle's recommendation to use DEFINE_DEBUGFS_ATTRIBUTE() instead of DEFINE_SIMPLE_ATTRIBUTE(). Regardless of whether or not the "significant overhead" incurred by debugfs_create_file() is actually meaningful, warnings from the script have led to a rash of low-quality patches that have sowed confusion and consumed maintainer time for little to no benefit. There have been no less than four attempts to "fix" KVM, and a quick search on lore shows that KVM is not alone. This reverts commit 5103068e. Link: https://lore.kernel.org/all/87tu2nbnz3.fsf@mpe.ellerman.id.au Link: https://lore.kernel.org/all/c0b98151-16b6-6d8f-1765-0f7d46682d60@redhat.com Link: https://lkml.kernel.org/r/20230706072954.4881-1-duminjie%40vivo.com Link: https://lore.kernel.org/all/Y2FsbufV00jbyF0B@google.com Link: https://lore.kernel.org/all/Y2ENJJ1YiSg5oHiy@orome Link: https://lore.kernel.org/all/7560b350e7b23786ce712118a9a504356ff1cca4.camel@kernel.orgSuggested-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Sean Christopherson authored
Verify that VM and vCPU binary stats files are usable even after userspace has put its last direct reference to the VM. This is a regression test for a UAF bug where KVM didn't gift the stats files a reference to the VM. Signed-off-by:
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Sean Christopherson authored
Expand the binary stats test to verify that a stats fd can be dup()'d and read, to (very) roughly simulate userspace passing around the file. Adding the dup() test is primarily an intermediate step towards verifying that userspace can read VM/vCPU stats before _and_ after userspace closes its copy of the VM fd; the dup() test itself is only mildly interesting. Signed-off-by:
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Sean Christopherson authored
Verify that KVM doesn't artificially limit KVM_GET_STATS_FD to a single file per VM/vCPU. There's no known use case for getting multiple stats fds, but it should work, and more importantly creating multiple files will make it easier to test that KVM correct manages VM refcounts for stats files. Signed-off-by:
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Sean Christopherson authored
Explicitly free the all-encompassing vcpus array in the binary stats test so that the test is consistent with respect to freeing all dynamically allocated resources (versus letting them be freed on exit). Signed-off-by:
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Sean Christopherson authored
Move the stats fd cleanup code into stats_test() and drop the superfluous vm_stats_test() and vcpu_stats_test() helpers in order to decouple creation of the stats file from consuming/testing the file (deduping code is a bonus). This will make it easier to test various edge cases related to stats, e.g. that userspace can dup() a stats fd, that userspace can have multiple stats files for a singleVM/vCPU, etc. Signed-off-by:
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Sean Christopherson authored
Use pread() with an explicit offset when reading the header and the header name for a binary stats fd so that the common helper and the binary stats test don't subtly rely on the file effectively being untouched, e.g. to allow multiple reads of the header, name, etc. Signed-off-by:
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Sean Christopherson authored
Grab a reference to KVM prior to installing VM and vCPU stats file descriptors to ensure the underlying VM and vCPU objects are not freed until the last reference to any and all stats fds are dropped. Note, the stats paths manually invoke fd_install() and so don't need to grab a reference before creating the file. Fixes: ce55c049 ("KVM: stats: Support binary stats retrieval for a VCPU") Fixes: fcfe1bae ("KVM: stats: Support binary stats retrieval for a VM") Reported-by:
Zheng Zhang <zheng.zhang@email.ucr.edu> Closes: https://lore.kernel.org/all/CAC_GQSr3xzZaeZt85k_RCBd5kfiOve8qXo7a81Cq53LuVQ5r=Q@mail.gmail.com Cc: stable@vger.kernel.org Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
Kees Cook <keescook@chromium.org> Message-Id: <20230711230131.648752-2-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
To allow running rseq and KVM's rseq selftests as statically linked binaries, initialize the various "trampoline" pointers to point directly at the expect glibc symbols, and skip the dlysm() lookups if the rseq size is non-zero, i.e. the binary is statically linked *and* the libc registered its own rseq. Define weak versions of the symbols so as not to break linking against libc versions that don't support rseq in any capacity. The KVM selftests in particular are often statically linked so that they can be run on targets with very limited runtime environments, i.e. test machines. Fixes: 233e667e ("selftests/rseq: Uplift rseq selftests for compatibility with glibc-2.35") Cc: Aaron Lewis <aaronlewis@google.com> Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Now that handle_fastpath_set_msr_irqoff() acquires kvm->srcu, i.e. allows dereferencing memslots during WRMSR emulation, drop the requirement that "next RIP" is valid. In hindsight, acquiring kvm->srcu would have been a better fix than avoiding the pastpath, but at the time it was thought that accessing SRCU-protected data in the fastpath was a one-off edge case. This reverts commit 5c30e810. Signed-off-by:
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Sean Christopherson authored
Temporarily acquire kvm->srcu for read when potentially emulating WRMSR in the VM-Exit fastpath handler, as several of the common helpers used during emulation expect the caller to provide SRCU protection. E.g. if the guest is counting instructions retired, KVM will query the PMU event filter when stepping over the WRMSR. dump_stack+0x85/0xdf lockdep_rcu_suspicious+0x109/0x120 pmc_event_is_allowed+0x165/0x170 kvm_pmu_trigger_event+0xa5/0x190 handle_fastpath_set_msr_irqoff+0xca/0x1e0 svm_vcpu_run+0x5c3/0x7b0 [kvm_amd] vcpu_enter_guest+0x2108/0x2580 Alternatively, check_pmu_event_filter() could acquire kvm->srcu, but this isn't the first bug of this nature, e.g. see commit 5c30e810 ("KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid"). Providing protection for the entirety of WRMSR emulation will allow reverting the aforementioned commit, and will avoid having to play whack-a-mole when new uses of SRCU-protected structures are inevitably added in common emulation helpers. Fixes: dfdeda67 ("KVM: x86/pmu: Prevent the PMU from counting disallowed events") Reported-by:
Greg Thelen <gthelen@google.com> Reported-by:
Aaron Lewis <aaronlewis@google.com> Signed-off-by:
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Sean Christopherson authored
Use vmread_error() to report VM-Fail on VMREAD for the "asm goto" case, now that trampoline case has yet another wrapper around vmread_error() to play nice with instrumentation. Signed-off-by:
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Sean Christopherson authored
Mark vmread_error_trampoline() as noinstr, and add a second trampoline for the CONFIG_CC_HAS_ASM_GOTO_OUTPUT=n case to enable instrumentation when handling VM-Fail on VMREAD. VMREAD is used in various noinstr flows, e.g. immediately after VM-Exit, and objtool rightly complains that the call to the error trampoline leaves a no-instrumentation section without annotating that it's safe to do so. vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0xc9: call to vmread_error_trampoline() leaves .noinstr.text section Note, strictly speaking, enabling instrumentation in the VM-Fail path isn't exactly safe, but if VMREAD fails the kernel/system is likely hosed anyways, and logging that there is a fatal error is more important than *maybe* encountering slightly unsafe instrumentation. Reported-by:
Su Hui <suhui@nfschina.com> Signed-off-by:
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Like Xu authored
As was attempted commit 14717e20 ("kvm: Conditionally register IRQ bypass consumer"): "if we don't support a mechanism for bypassing IRQs, don't register as a consumer. Initially this applied to AMD processors, but when AVIC support was implemented for assigned devices, kvm_arch_has_irq_bypass() was always returning true. We can still skip registering the consumer where enable_apicv or posted-interrupts capability is unsupported or globally disabled. This eliminates meaningless dev_info()s when the connect fails between producer and consumer", such as on Linux hosts where enable_apicv or posted-interrupts capability is unsupported or globally disabled. Cc: Alex Williamson <alex.williamson@redhat.com> Reported-by:
Yong He <alexyonghe@tencent.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217379Signed-off-by:
Like Xu <likexu@tencent.com> Message-Id: <20230724111236.76570-1-likexu@tencent.com> Signed-off-by:
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Peng Hao authored
The pid_table of ipiv is the persistent memory allocated by per-vcpu, which should be counted into the memory cgroup. Signed-off-by:
Peng Hao <flyingpeng@tencent.com> Message-Id: <CAPm50aLxCQ3TQP2Lhc0PX3y00iTRg+mniLBqNDOC=t9CLxMwwA@mail.gmail.com> Signed-off-by:
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Maxim Levitsky authored
The code was blindly assuming that kvm_cpu_get_interrupt never returns -1 when there is a pending interrupt. While this should be true, a bug in KVM can still cause this. If -1 is returned, the code before this patch was converting it to 0xFF, and 0xFF interrupt was injected to the guest, which results in an issue which was hard to debug. Add WARN_ON_ONCE to catch this case and skip the injection if this happens again. Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20230726135945.260841-4-mlevitsk@redhat.com> Signed-off-by:
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Maxim Levitsky authored
When the APICv is inhibited, the irr_pending optimization is used. Therefore, when kvm_apic_update_irr sets bits in the IRR, it must set irr_pending to true as well. Signed-off-by:
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Maxim Levitsky authored
If APICv is inhibited, then IPIs from peer vCPUs are done by atomically setting bits in IRR. This means, that when __kvm_apic_update_irr copies PIR to IRR, it has to modify IRR atomically as well. Signed-off-by:
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- 23 Jul, 2023 16 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-traceLinus Torvalds authored
Pull tracing fixes from Steven Rostedt: - Swapping the ring buffer for snapshotting (for things like irqsoff) can crash if the ring buffer is being resized. Disable swapping when this happens. The missed swap will be reported to the tracer - Report error if the histogram fails to be created due to an error in adding a histogram variable, in event_hist_trigger_parse() - Remove unused declaration of tracing_map_set_field_descr() * tag 'trace-v6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/histograms: Return an error if we fail to add histogram to hist_vars list ring-buffer: Do not swap cpu_buffer during resize process tracing: Remove unused extern declaration tracing_map_set_field_descr()
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Linus Torvalds authored
Merge tag 'kbuild-fixes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Fix stale help text in gconfig - Support *.S files in compile_commands.json - Flatten KBUILD_CFLAGS - Fix external module builds with Rust so that temporary files are created in the modules directories instead of the kernel tree * tag 'kbuild-fixes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: rust: avoid creating temporary files kbuild: flatten KBUILD_CFLAGS gen_compile_commands: add assembly files to compilation database kconfig: gconfig: correct program name in help text kconfig: gconfig: drop the Show Debug Info help text
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Miguel Ojeda authored
`rustc` outputs by default the temporary files (i.e. the ones saved by `-Csave-temps`, such as `*.rcgu*` files) in the current working directory when `-o` and `--out-dir` are not given (even if `--emit=x=path` is given, i.e. it does not use those for temporaries). Since out-of-tree modules are compiled from the `linux` tree, `rustc` then tries to create them there, which may not be accessible. Thus pass `--out-dir` explicitly, even if it is just for the temporary files. Similarly, do so for Rust host programs too. Reported-by:
Raphael Nestler <raphael.nestler@gmail.com> Closes: https://github.com/Rust-for-Linux/linux/issues/1015Reported-by:
Andrea Righi <andrea.righi@canonical.com> Tested-by: Raphael Nestler <raphael.nestler@gmail.com> # non-hostprogs Tested-by: Andrea Righi <andrea.righi@canonical.com> # non-hostprogs Fixes: 295d8398 ("kbuild: specify output names separately for each emission type from rustc") Cc: stable@vger.kernel.org Signed-off-by:
Miguel Ojeda <ojeda@kernel.org> Tested-by:
Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by:
Masahiro Yamada <masahiroy@kernel.org>
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull kvm fixes from Paolo Bonzini: "ARM: - Avoid pKVM finalization if KVM initialization fails - Add missing BTI instructions in the hypervisor, fixing an early boot failure on BTI systems - Handle MMU notifiers correctly for non hugepage-aligned memslots - Work around a bug in the architecture where hypervisor timer controls have UNKNOWN behavior under nested virt - Disable preemption in kvm_arch_hardware_enable(), fixing a kernel BUG in cpu hotplug resulting from per-CPU accessor sanity checking - Make WFI emulation on GICv4 systems robust w.r.t. preemption, consistently requesting a doorbell interrupt on vcpu_put() - Uphold RES0 sysreg behavior when emulating older PMU versions - Avoid macro expansion when initializing PMU register names, ensuring the tracepoints pretty-print the sysreg s390: - Two fixes for asynchronous destroy x86 fixes will come early next week" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: s390: pv: fix index value of replaced ASCE KVM: s390: pv: simplify shutdown and fix race KVM: arm64: Fix the name of sys_reg_desc related to PMU KVM: arm64: Correctly handle RES0 bits PMEVTYPER<n>_EL0.evtCount KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption KVM: arm64: Add missing BTI instructions KVM: arm64: Correctly handle page aging notifiers for unaligned memslot KVM: arm64: Disable preemption in kvm_arch_hardware_enable() KVM: arm64: Handle kvm_arm_init failure correctly in finalize_pkvm KVM: arm64: timers: Use CNTHCTL_EL2 when setting non-CNTKCTL_EL1 bits -
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4Linus Torvalds authored
Pull ext4 fixes from Ted Ts'o: "Bug and regression fixes for 6.5-rc3 for ext4's mballoc and jbd2's checkpoint code" * tag 'ext4_for_linus-6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix rbtree traversal bug in ext4_mb_use_preallocated ext4: fix off by one issue in ext4_mb_choose_next_group_best_avail() ext4: correct inline offset when handling xattrs in inode body jbd2: remove __journal_try_to_free_buffer() jbd2: fix a race when checking checkpoint buffer busy jbd2: Fix wrongly judgement for buffer head removing while doing checkpoint jbd2: remove journal_clean_one_cp_list() jbd2: remove t_checkpoint_io_list jbd2: recheck chechpointing non-dirty buffer
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
Pull smb client fix from Steve French: "Add minor debugging improvement. The change improves ability to read a network trace to debug problems on encrypted connections which are very common (e.g. using wireshark or tcpdump). That works today with tools like 'smbinfo keys /mnt/file' but requires passing in a filename on the mount (see e.g. [1]), but it often makes more sense to just pass in the mount point path (ie a directory not a filename). So this fix was needed to debug some types of problems (an obvious example is on an encrypted connection failing operations on an empty share or with no files in the root of the directory) - so you can simply pass in the 'smbinfo keys <mntpoint>' and get the information that wireshark needs" Link: https://wiki.samba.org/index.php/Wireshark_Decryption [1] * tag '6.5-rc2-smb3-client-fixes-ver2' of git://git.samba.org/sfrench/cifs-2.6: cifs: update internal module version number for cifs.ko cifs: allow dumping keys for directories too
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Paolo Bonzini authored
Merge tag 'kvm-s390-master-6.5-1' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD Two fixes for asynchronous destroy
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Paolo Bonzini authored
Merge tag 'kvmarm-fixes-6.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 6.5, part #1 - Avoid pKVM finalization if KVM initialization fails - Add missing BTI instructions in the hypervisor, fixing an early boot failure on BTI systems - Handle MMU notifiers correctly for non hugepage-aligned memslots - Work around a bug in the architecture where hypervisor timer controls have UNKNOWN behavior under nested virt. - Disable preemption in kvm_arch_hardware_enable(), fixing a kernel BUG in cpu hotplug resulting from per-CPU accessor sanity checking. - Make WFI emulation on GICv4 systems robust w.r.t. preemption, consistently requesting a doorbell interrupt on vcpu_put() - Uphold RES0 sysreg behavior when emulating older PMU versions - Avoid macro expansion when initializing PMU register names, ensuring the tracepoints pretty-print the sysreg.
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Mohamed Khalfella authored
Commit 6018b585 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") added a check to fail histogram creation if save_hist_vars() failed to add histogram to hist_vars list. But the commit failed to set ret to failed return code before jumping to unregister histogram, fix it. Link: https://lore.kernel.org/linux-trace-kernel/20230714203341.51396-1-mkhalfella@purestorage.com Cc: stable@vger.kernel.org Fixes: 6018b585 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") Signed-off-by:
Mohamed Khalfella <mkhalfella@purestorage.com> Signed-off-by:
Steven Rostedt (Google) <rostedt@goodmis.org>
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Chen Lin authored
When ring_buffer_swap_cpu was called during resize process, the cpu buffer was swapped in the middle, resulting in incorrect state. Continuing to run in the wrong state will result in oops. This issue can be easily reproduced using the following two scripts: /tmp # cat test1.sh //#! /bin/sh for i in `seq 0 100000` do echo 2000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 echo 5000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 done /tmp # cat test2.sh //#! /bin/sh for i in `seq 0 100000` do echo irqsoff > /sys/kernel/debug/tracing/current_tracer sleep 1 echo nop > /sys/kernel/debug/tracing/current_tracer sleep 1 done /tmp # ./test1.sh & /tmp # ./test2.sh & A typical oops log is as follows, sometimes with other different oops logs. [ 231.711293] WARNING: CPU: 0 PID: 9 at kernel/trace/ring_buffer.c:2026 rb_update_pages+0x378/0x3f8 [ 231.713375] Modules linked in: [ 231.714735] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec2 #15 [ 231.716750] Hardware name: linux,dummy-virt (DT) [ 231.718152] Workqueue: events update_pages_handler [ 231.719714] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 231.721171] pc : rb_update_pages+0x378/0x3f8 [ 231.722212] lr : rb_update_pages+0x25c/0x3f8 [ 231.723248] sp : ffff800082b9bd50 [ 231.724169] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 231.726102] x26: 0000000000000001 x25: fffffffffffff010 x24: 0000000000000ff0 [ 231.728122] x23: ffff0000c3a0b600 x22: ffff0000c3a0b5c0 x21: fffffffffffffe0a [ 231.730203] x20: ffff0000c3a0b600 x19: ffff0000c0102400 x18: 0000000000000000 [ 231.732329] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffe7aa8510 [ 231.734212] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000002 [ 231.736291] x11: ffff8000826998a8 x10: ffff800082b9baf0 x9 : ffff800081137558 [ 231.738195] x8 : fffffc00030e82c8 x7 : 0000000000000000 x6 : 0000000000000001 [ 231.740192] x5 : ffff0000ffbafe00 x4 : 0000000000000000 x3 : 0000000000000000 [ 231.742118] x2 : 00000000000006aa x1 : 0000000000000001 x0 : ffff0000c0007208 [ 231.744196] Call trace: [ 231.744892] rb_update_pages+0x378/0x3f8 [ 231.745893] update_pages_handler+0x1c/0x38 [ 231.746893] process_one_work+0x1f0/0x468 [ 231.747852] worker_thread+0x54/0x410 [ 231.748737] kthread+0x124/0x138 [ 231.749549] ret_from_fork+0x10/0x20 [ 231.750434] ---[ end trace 0000000000000000 ]--- [ 233.720486] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 233.721696] Mem abort info: [ 233.721935] ESR = 0x0000000096000004 [ 233.722283] EC = 0x25: DABT (current EL), IL = 32 bits [ 233.722596] SET = 0, FnV = 0 [ 233.722805] EA = 0, S1PTW = 0 [ 233.723026] FSC = 0x04: level 0 translation fault [ 233.723458] Data abort info: [ 233.723734] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 233.724176] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 233.724589] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 233.725075] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000104943000 [ 233.725592] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 233.726231] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 233.726720] Modules linked in: [ 233.727007] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec2 #15 [ 233.727777] Hardware name: linux,dummy-virt (DT) [ 233.728225] Workqueue: events update_pages_handler [ 233.728655] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 233.729054] pc : rb_update_pages+0x1a8/0x3f8 [ 233.729334] lr : rb_update_pages+0x154/0x3f8 [ 233.729592] sp : ffff800082b9bd50 [ 233.729792] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 233.730220] x26: 0000000000000000 x25: ffff800082a8b840 x24: ffff0000c0102418 [ 233.730653] x23: 0000000000000000 x22: fffffc000304c880 x21: 0000000000000003 [ 233.731105] x20: 00000000000001f4 x19: ffff0000c0102400 x18: ffff800082fcbc58 [ 233.731727] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001 [ 233.732282] x14: ffff8000825fe0c8 x13: 0000000000000001 x12: 0000000000000000 [ 233.732709] x11: ffff8000826998a8 x10: 0000000000000ae0 x9 : ffff8000801b760c [ 233.733148] x8 : fefefefefefefeff x7 : 0000000000000018 x6 : ffff0000c03298c0 [ 233.733553] x5 : 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000 [ 233.733972] x2 : ffff0000c3a0b600 x1 : 0000000000000000 x0 : 0000000000000000 [ 233.734418] Call trace: [ 233.734593] rb_update_pages+0x1a8/0x3f8 [ 233.734853] update_pages_handler+0x1c/0x38 [ 233.735148] process_one_work+0x1f0/0x468 [ 233.735525] worker_thread+0x54/0x410 [ 233.735852] kthread+0x124/0x138 [ 233.736064] ret_from_fork+0x10/0x20 [ 233.736387] Code: 92400000 910006b5 aa000021 aa0303f7 (f9400060) [ 233.736959] ---[ end trace 0000000000000000 ]--- After analysis, the seq of the error is as follows [1-5]: int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu_id) { for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //1. get cpu_buffer, aka cpu_buffer(A) ... ... schedule_work_on(cpu, &cpu_buffer->update_pages_work); //2. 'update_pages_work' is queue on 'cpu', cpu_buffer(A) is passed to // update_pages_handler, do the update process, set 'update_done' in // complete(&cpu_buffer->update_done) and to wakeup resize process. //----> //3. Just at this moment, ring_buffer_swap_cpu is triggered, //cpu_buffer(A) be swaped to cpu_buffer(B), the max_buffer. //ring_buffer_swap_cpu is called as the 'Call trace' below. Call trace: dump_backtrace+0x0/0x2f8 show_stack+0x18/0x28 dump_stack+0x12c/0x188 ring_buffer_swap_cpu+0x2f8/0x328 update_max_tr_single+0x180/0x210 check_critical_timing+0x2b4/0x2c8 tracer_hardirqs_on+0x1c0/0x200 trace_hardirqs_on+0xec/0x378 el0_svc_common+0x64/0x260 do_el0_svc+0x90/0xf8 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb8 el0_sync+0x180/0x1c0 //<---- /* wait for all the updates to complete */ for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //4. get cpu_buffer, cpu_buffer(B) is used in the following process, //the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong. //for example, cpu_buffer(A)->update_done will leave be set 1, and will //not 'wait_for_completion' at the next resize round. if (!cpu_buffer->nr_pages_to_update) continue; if (cpu_online(cpu)) wait_for_completion(&cpu_buffer->update_done); cpu_buffer->nr_pages_to_update = 0; } ... } //5. the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong, //Continuing to run in the wrong state, then oops occurs. Link: https://lore.kernel.org/linux-trace-kernel/202307191558478409990@zte.com.cnSigned-off-by:Chen Lin <chen.lin5@zte.com.cn> Signed-off-by:
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YueHaibing authored
Since commit 08d43a5f ("tracing: Add lock-free tracing_map"), this is never used, so can be removed. Link: https://lore.kernel.org/linux-trace-kernel/20230722032123.24664-1-yuehaibing@huawei.com Cc: <mhiramat@kernel.org> Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Signed-off-by:
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Alexey Dobriyan authored
Make it slightly easier to see which compiler options are added and removed (and not worry about column limit too!). Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by:
Nicolas Schier <n.schier@avm.de> Signed-off-by:
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Benjamin Gray authored
Like C source files, tooling can find it useful to have the assembly source file compilation recorded. The .S extension appears to used across all architectures. Signed-off-by:
Benjamin Gray <bgray@linux.ibm.com> Reviewed-by:
Fangrui Song <maskray@google.com> Reviewed-by:
Nathan Chancellor <nathan@kernel.org> Reviewed-by:
Nick Desaulniers <ndesaulniers@google.com> Signed-off-by:
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Ojaswin Mujoo authored
During allocations, while looking for preallocations(PA) in the per inode rbtree, we can't do a direct traversal of the tree because ext4_mb_discard_group_preallocation() can paralelly mark the pa deleted and that can cause direct traversal to skip some entries. This was leading to a BUG_ON() being hit [1] when we missed a PA that could satisfy our request and ultimately tried to create a new PA that would overlap with the missed one. To makes sure we handle that case while still keeping the performance of the rbtree, we make use of the fact that the only pa that could possibly overlap the original goal start is the one that satisfies the below conditions: 1. It must have it's logical start immediately to the left of (ie less than) original logical start. 2. It must not be deleted To find this pa we use the following traversal method: 1. Descend into the rbtree normally to find the immediate neighboring PA. Here we keep descending irrespective of if the PA is deleted or if it overlaps with our request etc. The goal is to find an immediately adjacent PA. 2. If the found PA is on right of original goal, use rb_prev() to find the left adjacent PA. 3. Check if this PA is deleted and keep moving left with rb_prev() until a non deleted PA is found. 4. This is the PA we are looking for. Now we can check if it can satisfy the original request and proceed accordingly. This approach also takes care of having deleted PAs in the tree. (While we are at it, also fix a possible overflow bug in calculating the end of a PA) [1] https://lore.kernel.org/linux-ext4/CA+G9fYv2FRpLqBZf34ZinR8bU2_ZRAUOjKAD3+tKRFaEQHtt8Q@mail.gmail.com/ Cc: stable@kernel.org # 6.4 Fixes: 38727786 ("ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list") Signed-off-by:
Ojaswin Mujoo <ojaswin@linux.ibm.com> Reported-by:
Naresh Kamboju <naresh.kamboju@linaro.org> Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Tested-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Link: https://lore.kernel.org/r/edd2efda6a83e6343c5ace9deea44813e71dbe20.1690045963.git.ojaswin@linux.ibm.comSigned-off-by:
Theodore Ts'o <tytso@mit.edu>
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Ojaswin Mujoo authored
In ext4_mb_choose_next_group_best_avail(), we want the start order to be 1 less than goal length and the min_order to be, at max, 1 more than the original length. This commit fixes an off by one issue that arose due to the fact that 1 << fls(n) > (n). After all the processing: order = 1 order below goal len min_order = maximum of the three:- - order - trim_order - 1 order below B2C(s_stripe) - 1 order above original len Cc: stable@kernel.org Fixes: 33122aa930 ("ext4: Add allocation criteria 1.5 (CR1_5)") Signed-off-by:
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