- 25 Jul, 2023 29 commits
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Yi Liu authored
This saves some lines when adding the kvm get logic for the vfio_device cdev path. This also renames _vfio_device_get_kvm_safe() to be vfio_device_get_kvm_safe(). Suggested-by:
Jason Gunthorpe <jgg@nvidia.com> Reviewed-by:
Zhenzhong Duan <zhenzhong.duan@intel.com> Tested-by:
Yanting Jiang <yanting.jiang@intel.com> Signed-off-by:
Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-20-yi.l.liu@intel.comSigned-off-by:
Alex Williamson <alex.williamson@redhat.com>
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Yi Liu authored
This adds cdev support for vfio_device. It allows the user to directly open a vfio device w/o using the legacy container/group interface, as a prerequisite for supporting new iommu features like nested translation and etc. The device fd opened in this manner doesn't have the capability to access the device as the fops open() doesn't open the device until the successful VFIO_DEVICE_BIND_IOMMUFD ioctl which will be added in a later patch. With this patch, devices registered to vfio core would have both the legacy group and the new device interfaces created. - group interface : /dev/vfio/$groupID - device interface: /dev/vfio/devices/vfioX - normal device ("X" is a unique number across vfio devices) For a given device, the user can identify the matching vfioX by searching the vfio-dev folder under the sysfs path of the device. Take PCI device (0000:6a:01.0) as an example, /sys/bus/pci/devices/0000\:6a\:01.0/vfio-dev/vfioX implies the matching vfioX under /dev/vfio/devices/, and vfio-dev/vfioX/dev contains the major:minor number of the matching /dev/vfio/devices/vfioX. The user can get device fd by opening the /dev/vfio/devices/vfioX. The vfio_device cdev logic in this patch: *) __vfio_register_dev() path ends up doing cdev_device_add() for each vfio_device if VFIO_DEVICE_CDEV configured. *) vfio_unregister_group_dev() path does cdev_device_del(); cdev interface does not support noiommu devices, so VFIO only creates the legacy group interface for the physical devices that do not have IOMMU. noiommu users should use the legacy group interface. Reviewed-by:Kevin Tian <kevin.tian@intel.com> Reviewed-by:
Terrence Xu <terrence.xu@intel.com> Tested-by:
Nicolin Chen <nicolinc@nvidia.com> Tested-by:
Matthew Rosato <mjrosato@linux.ibm.com> Tested-by:
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by:
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Yi Liu authored
device_del() destroys the vfio-dev/vfioX under the sysfs for vfio_device. There is no reason to keep it while the device is going to be unregistered. This movement is also a preparation for adding vfio_device cdev. Kernel should remove the cdev node of the vfio_device to avoid new registration refcount increment while the device is going to be unregistered. Reviewed-by:
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Yi Liu authored
This avoids endless vfio_device refcount increment by userspace, which would keep blocking the vfio_unregister_group_dev(). Reviewed-by:
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Yi Liu authored
This prepares for adding DETACH ioctl for emulated VFIO devices. Reviewed-by:
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Nicolin Chen authored
Previously, the detach routine is only done by the destroy(). And it was called by vfio_iommufd_emulated_unbind() when the device runs close(), so all the mappings in iopt were cleaned in that setup, when the call trace reaches this detach() routine. Now, there's a need of a detach uAPI, meaning that it does not only need a new iommufd_access_detach() API, but also requires access->ops->unmap() call as a cleanup. So add one. However, leaving that unprotected can introduce some potential of a race condition during the pin_/unpin_pages() call, where access->ioas->iopt is getting referenced. So, add an ioas_lock to protect the context of iopt referencings. Also, to allow the iommufd_access_unpin_pages() callback to happen via this unmap() call, add an ioas_unpin pointer, so the unpin routine won't be affected by the "access->ioas = NULL" trick. Reviewed-by:
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Yi Liu authored
This prepares for adding DETACH ioctl for physical VFIO devices. Reviewed-by:
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Yi Liu authored
.bind_iommufd() will generate an ID to represent this bond, which is needed by userspace for further usage. Store devid in vfio_device_file to avoid passing the pointer in multiple places. Reviewed-by:
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Yi Liu authored
This aligns the bind/attach logic with the coming vfio device cdev support. Reviewed-by:
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Yi Liu authored
This moves the noiommu compat validation logic into vfio_df_group_open(). This is more consistent with what will be done in vfio device cdev path. Reviewed-by:
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Yi Liu authored
VFIO group has historically allowed multi-open of the device FD. This was made secure because the "open" was executed via an ioctl to the group FD which is itself only single open. However, no known use of multiple device FDs today. It is kind of a strange thing to do because new device FDs can naturally be created via dup(). When we implement the new device uAPI (only used in cdev path) there is no natural way to allow the device itself from being multi-opened in a secure manner. Without the group FD we cannot prove the security context of the opener. Thus, when moving to the new uAPI we block the ability of opening a device multiple times. Given old group path still allows it we store a vfio_group pointer in struct vfio_device_file to differentiate. Reviewed-by:
Eric Auger <eric.auger@redhat.com> Tested-by:
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Yi Liu authored
This is for counting the devices that are opened via the cdev path. This count is increased and decreased by the cdev path. The group path checks it to achieve exclusion with the cdev path. With this, only one path (group path or cdev path) will claim DMA ownership. This avoids scenarios in which devices within the same group may be opened via different paths. Reviewed-by:
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Yi Liu authored
Allow the vfio_device file to be in a state where the device FD is opened but the device cannot be used by userspace (i.e. its .open_device() hasn't been called). This inbetween state is not used when the device FD is spawned from the group FD, however when we create the device FD directly by opening a cdev it will be opened in the blocked state. The reason for the inbetween state is that userspace only gets a FD but doesn't gain access permission until binding the FD to an iommufd. So in the blocked state, only the bind operation is allowed. Completing bind will allow user to further access the device. This is implemented by adding a flag in struct vfio_device_file to mark the blocked state and using a simple smp_load_acquire() to obtain the flag value and serialize all the device setup with the thread accessing this device. Following this lockless scheme, it can safely handle the device FD unbound->bound but it cannot handle bound->unbound. To allow this we'd need to add a lock on all the vfio ioctls which seems costly. So once device FD is bound, it remains bound until the FD is closed. Suggested-by:
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Yi Liu authored
This avoids passing too much parameters in multiple functions. Per the input parameter change, rename the function to be vfio_df_open/close(). Reviewed-by:
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Yi Liu authored
This defines KVM_DEV_VFIO_FILE* and make alias with KVM_DEV_VFIO_GROUP*. Old userspace uses KVM_DEV_VFIO_GROUP* works as well. Reviewed-by:
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Yi Liu authored
This renames kvm_vfio_group related helpers to prepare for accepting vfio device fd. No functional change is intended. Reviewed-by:
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Yi Liu authored
This makes the vfio file kAPIs to accept vfio device files, also a preparation for vfio device cdev support. For the kvm set with vfio device file, kvm pointer is stored in struct vfio_device_file, and use kvm_ref_lock to protect kvm set and kvm pointer usage within VFIO. This kvm pointer will be set to vfio_device after device file is bound to iommufd in the cdev path. Reviewed-by:
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Yi Liu authored
This prepares for making the below kAPIs to accept both group file and device file instead of only vfio group file. bool vfio_file_enforced_coherent(struct file *file); void vfio_file_set_kvm(struct file *file, struct kvm *kvm); Reviewed-by:
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Yi Liu authored
This is preparation for adding vfio device cdev support. vfio device cdev requires: 1) A per device file memory to store the kvm pointer set by KVM. It will be propagated to vfio_device:kvm after the device cdev file is bound to an iommufd. 2) A mechanism to block device access through device cdev fd before it is bound to an iommufd. To address the above requirements, this adds a per device file structure named vfio_device_file. For now, it's only a wrapper of struct vfio_device pointer. Other fields will be added to this per file structure in future commits. Reviewed-by:
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Yi Liu authored
This is the way user to invoke hot-reset for the devices opened by cdev interface. User should check the flag VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED in the output of VFIO_DEVICE_GET_PCI_HOT_RESET_INFO ioctl before doing hot-reset for cdev devices. Suggested-by:
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Yi Liu authored
This copies the vfio_pci_dependent_device to userspace during looping each affected device for reporting vfio_pci_hot_reset_info. This avoids counting the affected devices and allocating a potential large buffer to store the vfio_pci_dependent_device of all the affected devices before copying them to userspace. Suggested-by:
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Yi Liu authored
This allows VFIO_DEVICE_GET_PCI_HOT_RESET_INFO ioctl use the iommufd_ctx of the cdev device to check the ownership of the other affected devices. When VFIO_DEVICE_GET_PCI_HOT_RESET_INFO is called on an IOMMUFD managed device, the new flag VFIO_PCI_HOT_RESET_FLAG_DEV_ID is reported to indicate the values returned are IOMMUFD devids rather than group IDs as used when accessing vfio devices through the conventional vfio group interface. Additionally the flag VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED will be reported in this mode if all of the devices affected by the hot-reset are owned by either virtue of being directly bound to the same iommufd context as the calling device, or implicitly owned via a shared IOMMU group. Suggested-by:
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Yi Liu authored
There are drivers that need to search vfio_device within a given dev_set. e.g. vfio-pci. So add a helper. vfio_pci_is_device_in_set() now returns -EBUSY in commit a882c16a ("vfio/pci: Change vfio_pci_try_bus_reset() to use the dev_set") where it was trying to preserve the return of vfio_pci_try_zap_and_vma_lock_cb(). However, it makes more sense to return -ENODEV. Suggested-by:
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Yi Liu authored
This can be used to differentiate whether to report group_id or devid in the revised VFIO_DEVICE_GET_PCI_HOT_RESET_INFO ioctl. At this moment, no cdev path yet, so the vfio_device_cdev_opened() helper always returns false. Reviewed-by:
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Yi Liu authored
This is needed by the vfio-pci driver to report affected devices in the hot-reset for a given device. Reviewed-by:
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Yi Liu authored
This adds the helper to check if any device within the given iommu_group has been bound with the iommufd_ctx. This is helpful for the checking on device ownership for the devices which have not been bound but cannot be bound to any other iommufd_ctx as the iommu_group has been bound. Reviewed-by:
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Yi Liu authored
With this reservation, IOMMUFD users can encode the negative IDs for specific purposes. e.g. VFIO needs two reserved values to tell userspace the ID returned is not valid but has other meaning. Reviewed-by:
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Yi Liu authored
This prepares to add another method for hot reset. The major hot reset logic are moved to vfio_pci_ioctl_pci_hot_reset_groups(). No functional change is intended. Suggested-by:
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Yi Liu authored
This suits more on what the code does. Reviewed-by:
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- 23 Jul, 2023 11 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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