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Tue, 21 Apr 2026 04:17:52 -0700 (PDT) MIME-Version: 1.0 From: Zw Tang Date: Tue, 21 Apr 2026 19:17:40 +0800 X-Gm-Features: AQROBzCvxTzVOatYGD3oQlMzZmTAz5McY1A204T_VliE2k6DNBeXHfpitVDrZ9A Message-ID: Subject: [BUG] WARNING in workingset_activation triggered by KVM page fault path on Linux 7.0.0-08391-g1d51b370a0f8 To: linux-mm@kvack.org, akpm@linux-foundation.org, hannes@cmpxchg.org Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, seanjc@google.com Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: jr89wwn4jxzjeoh7gz8bfa3gkx8ww617 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: E617A10000C X-HE-Tag: 1776770273-866111 X-HE-Meta: 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 9MYzP2iQ WCQiMt23avCwYQeK1XApEobXTX9LsOrR7Sb4E0CLbDA89MiShGVnrrkpw8hmIfRm3I6db4dKL6kfsblqvCuYH18XXHHuwdLkUsGckfVtF7395q1miI2P08vTmB0RpNl+sd0Wp4NZJFt7SQR7KPrLc43VmzfjQwn2MPXVx3ZW0gYv3MmZUZqi68GaFp2JEXVk4MjveTB0ENwz2DptIYuvJJLPILT4fnqJZXnyILe5oCnymmqvcwk+yD8KIZybDydQeHmxc86ObK2tHX+O6wL+GjXvHHYnzyicZo4TI4S4klo/VMJvzCngXNBu+pey/rmnDXEdDybDrwX+7y2xqRTAqDByjG9zc/Lk+p2oSoTOraYsox8s8HUfQ7rbbnhToZwBSCNkqI/NXniaNEndeC+nu5Gop8+t99Y8AyrdFhiuKP8deNQT3+tluAb+yTwJXd/aA0xDDPduCUmtgRBtxxt2Ef48TEQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, I am reporting a WARNING in workingset_activation() triggered by a syzkaller C reproducer on Linux 7.0.0-08391-g1d51b370a0f8. The warning is hit from the KVM page fault path: kvm_set_page_accessed() -> folio_mark_accessed() -> workingset_activation(). At first glance this looks more like an MM/workingset issue than a KVM-specific bug, although KVM/SVM is the trigger path. Reproducer: C reproducer: pastebin.com/raw/zzNSd9HK console output: pastebin.com/raw/TuipfpyA kernel config: pastebin.com/raw/aq1V3cLk Kernel: HEAD commit: 1d51b370a0f8 git tree: torvalds/linux kernel version: 7.0.0-08391-g1d51b370a0f8 #1 PREEMPT(lazy) (QEMU Standard PC, Q35) The warning is: WARNING in workingset_activation Log excerpt: WARNING: include/linux/memcontrol.h:381 at workingset_activation+0x466/0x540, CPU#1: repro/238 Call Trace: folio_mark_accessed+0x1d3/0x650 kvm_set_page_accessed+0x5a/0x70 kvm_release_page_clean+0x26/0x180 direct_page_fault+0x553/0x11a0 kvm_mmu_page_fault+0x35b/0x2020 kvm_handle_page_fault+0x1aa/0x380 svm_invoke_exit_handler+0x7a/0xe0 svm_handle_exit+0x416/0x7f0 vcpu_enter_guest+0x26ad/0x49c0 kvm_arch_vcpu_ioctl_run+0x697/0x25e0 kvm_vcpu_ioctl+0x737/0x1610 __x64_sys_ioctl+0x192/0x220 do_syscall_64+0x117/0xfc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 The reproducer appears to drive KVM into a guest page fault flow that marks a folio as accessed, and the warning is then emitted inside workingset_activation(). Because the RIP is in workingset_activation() itself, this may indicate a problem in workingset/LRU or memcg/lruvec handling, with KVM only serving as the trigger path. Please let me know if I should also send this to additional KVM x86 maintainers, but mm/workingset.c seems to be the primary fault location. Thanks.