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My test PR - #5

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Jul 8, 2026
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My test PR#5
6by9 merged 9 commits into
rpi-6.18.yfrom
rpi-6.18.y-workflows

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@6by9 6by9 commented Jul 8, 2026

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Quick test for my new workflow

6by9 and others added 9 commits July 8, 2026 17:38
Does NOT include the clock and IRQ changes.

Signed-off-by: John Cox <jc@kynesim.co.uk>
To avoid user complaints that /dev/video0 isn't their USB
webcam, add downstream patch that allows setting the preferred
video device number.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Upstream will take the multi-planar SAND format, but add back
in the downstream single planar variant for backwards compatibility

This includes the fixups that were present as separate patches in
earlier versions.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
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6by9 force-pushed the rpi-6.18.y-workflows branch from 83ff200 to 5ad671d Compare July 8, 2026 17:49
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6by9 merged commit 5ad671d into rpi-6.18.y Jul 8, 2026
6by9 pushed a commit that referenced this pull request Aug 3, 2026
[ Upstream commit b23705e ]

strset_add_str_mem() might reallocate the strset data buffer in order to
accommodate the provided string 's'. However, if 's' points to a string
already present in the buffer, it becomes dangling after the realloc.
This leads to a use-after-free when attempting to memcpy() the string
into the new buffer.

One scenario that triggers this problematic path is when resolve_btfids
attempts to patch kfunc prototypes using existing BTF parameter names:

 | resolve_btfids: function bpf_list_push_back_impl already exists in BTF
 | Segmentation fault (core dumped)

Compiling resolve_btfids with fsanitize=address generates a detailed
report of the UAF:

 | =================================================================
 | ERROR: AddressSanitizer: heap-use-after-free on address 0x7f4c4a500bd4
 | ==1507892==ERROR: AddressSanitizer: heap-use-after-free on address 0x7f4c4a500bd4 at pc 0x55d25155a2a8 bp 0x7ffcef879060 sp 0x7ffcef878818
 | READ of size 5 at 0x7f4c4a500bd4 thread T0
 |     #0 0x55d25155a2a7 in memcpy (tools/bpf/resolve_btfids/resolve_btfids+0xcf2a7)
 |     #1 0x55d2515d708e in strset__add_str tools/lib/bpf/strset.c:162:2
 |     #2 0x55d2515c730b in btf__add_str tools/lib/bpf/btf.c:2109:8
 |     #3 0x55d2515c9020 in btf__add_func_param tools/lib/bpf/btf.c:3108:14
 |     #4 0x55d25159f0b5 in process_kfunc_with_implicit_args tools/bpf/resolve_btfids/main.c:1196:9
 |     #5 0x55d25159e004 in btf2btf tools/bpf/resolve_btfids/main.c:1229:9
 |     #6 0x55d25159cee7 in main tools/bpf/resolve_btfids/main.c:1535:6
 |     #7 0x7f4c78e29f76 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
 |     #8 0x7f4c78e2a026 in __libc_start_main csu/../csu/libc-start.c:360:3
 |     raspberrypi#9 0x55d2514bb860 in _start (tools/bpf/resolve_btfids/resolve_btfids+0x30860)
 |
 | 0x7f4c4a500bd4 is located 13268 bytes inside of 2829000-byte region [0x7f4c4a4fd800,0x7f4c4a7b02c8)
 | freed by thread T0 here:
 |     #0 0x55d25155b700 in realloc (tools/bpf/resolve_btfids/resolve_btfids+0xd0700)
 |     #1 0x55d2515c426c in libbpf_reallocarray tools/lib/bpf/./libbpf_internal.h:220:9
 |     #2 0x55d2515c426c in libbpf_add_mem tools/lib/bpf/btf.c:224:13
 |
 | previously allocated by thread T0 here:
 |     #0 0x55d25155b2e3 in malloc (tools/bpf/resolve_btfids/resolve_btfids+0xd02e3)
 |     #1 0x55d2515d6e7d in strset__new tools/lib/bpf/strset.c:58:20

While resolve_btfids could be refactored to avoid this call path, let's
instead fix this issue at the source in strset__add_str() and avoid
similar scenarios.

Let's check if set->strs_data was reallocated and whether 's' points to
an internal string within the old strset buffer. In such case, 's' is
reconstructed to point to the new buffer.

While already here, also fix strset__find_str() which suffers from the
same problem by factoring out the common operations into a new helper
function strset_str_append().

Fixes: 90d76d3 ("libbpf: Extract internal set-of-strings datastructure APIs")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Suggested-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260523162722.2718940-1-cmllamas@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
6by9 pushed a commit that referenced this pull request Sep 2, 2026
…w page

commit 5ec42d5 upstream.

Explicitly clear role.invalid when deriving a child shadow page's role from
its parent to harden against bugs elsewhere in KVM, as violating KVM's
invariant that invalid pages are NOT on the list of active MMU pages leads
to use-after-free due to __kvm_mmu_prepare_zap_page() using list_add()
instead of list_move() when processing an invalid shadow page, i.e. makes a
bad situation far worse.

Yell loudly if the parent is invalid, as it means KVM has missed a validity
check, i.e. KVM is attempting to map memory using an invalid/obsolete root,
but continue on as the child is otherwise still a valid shadow page.

  ==================================================================
  BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
  Write of size 8 at addr ff11000153dd1368 by task repro/853

  CPU: 1 UID: 1000 PID: 853 Comm: repro Not tainted 7.2.0-rc2-3aec122bdcaf-next-vm #5 PREEMPT
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  Call Trace:
   <TASK>
   dump_stack_lvl+0x4b/0x70
   print_report+0x153/0x49c
   kasan_report+0xbc/0xf0
   __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
   mmu_alloc_root+0x141/0x320 [kvm]
   kvm_mmu_load+0x612/0x20f0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x3dd5/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   </TASK>

  Allocated by task 853:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x14/0x30
   __kasan_slab_alloc+0x5f/0x70
   kmem_cache_alloc_noprof+0xfe/0x2e0
   __kvm_mmu_topup_memory_cache+0x135/0x530 [kvm]
   paging64_page_fault+0x318/0x1e30 [kvm]
   kvm_mmu_do_page_fault+0x21d/0x630 [kvm]
   kvm_mmu_page_fault+0x18c/0x17b0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x1f35/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

  Freed by task 853:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x14/0x30
   kasan_save_free_info+0x3b/0x60
   __kasan_slab_free+0x43/0x70
   kmem_cache_free+0xe2/0x400
   kvm_mmu_commit_zap_page.part.0+0x1e2/0x310 [kvm]
   kvm_mmu_free_roots+0x283/0x560 [kvm]
   kvm_arch_vcpu_ioctl_run+0x33c8/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Fixes: a770f6f ("KVM: MMU: Inherit a shadow page's guest level count from vcpu setup")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6by9 pushed a commit that referenced this pull request Sep 2, 2026
[ Upstream commit 9910e83 ]

Cancel (and flush) the I/O APIC's delayed EOI handling work during the
"pre VM destroy" phase, before vCPUs are destroyed, as processing the EOI
broadcast will inject another IRQ if the line is asserted, i.e. will try
to deliver an IRQ to the target vCPU(s).  Canceling the work after vCPUs
are destroyed leads to UAF if the delayed work is processed after vCPUs are
destroyed.

  BUG: KASAN: slab-use-after-free in __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250
  Read of size 8 at addr ffff8880499abea0 by task kworker/1:2/1218

  CPU: 1 UID: 0 PID: 1218 Comm: kworker/1:2 Not tainted 7.1.0-rc7 #5 PREEMPT(lazy)
  Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
  Workqueue: events kvm_ioapic_eoi_inject_work
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:94
   dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
   print_address_description mm/kasan/report.c:378
   print_report+0x139/0x4ad mm/kasan/report.c:482
   kasan_report+0xe4/0x1d0 mm/kasan/report.c:595
   __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250
   __kvm_irq_delivery_to_apic+0xd8/0xbf0 arch/x86/kvm/lapic.c:1345
   kvm_irq_delivery_to_apic arch/x86/kvm/lapic.h:129
   ioapic_service+0x308/0x590 arch/x86/kvm/ioapic.c:492
   kvm_ioapic_eoi_inject_work+0x13c/0x190 arch/x86/kvm/ioapic.c:532
   process_one_work+0xa59/0x19a0 kernel/workqueue.c:3314
   process_scheduled_works kernel/workqueue.c:3397
   worker_thread+0x5eb/0xe50 kernel/workqueue.c:3478
   kthread+0x370/0x450 kernel/kthread.c:436
   ret_from_fork+0x72b/0xd30 arch/x86/kernel/process.c:158
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   </TASK>

Note, the VM is unreachable once kvm_destroy_vm() starts, and scheduling
new work via kvm_ioapic_send_eoi() can only be done via KVM_RUN, i.e.
requires a live vCPU.

Alternatively, KVM could simply destroy the I/O APIC during the "pre" phase
of VM destruction, but that gets more than a bit sketchy as KVM expects the
I/O APIC to exist if ioapic_in_kernel() is true, and nested virtualization
in particular has a bad habit of touching VM-scope state during vCPU
destruction.  E.g. attempting to free the PIC during the pre phase would
lead to a NULL pointer dereference in kvm_cpu_has_extint(), and it's not
hard to imagine the I/O APIC having a similar flaw.

Fixes: 17bcd71 ("KVM: x86: Free vCPUs before freeing VM state")
Reported-by: <zdi-disclosures@trendmicro.com>
Reported-by: Zhong Wang <wangzhong.c0ss4ck@bytedance.com>
Reported-by: Xuanqing Shi <shixuanqing.11@bytedance.com>
Cc: stable@vger.kernel.org
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260727171718.543491-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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