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Sun, 15 Feb 2026 11:05:23 -0800 (PST) Date: Sun, 15 Feb 2026 11:05:23 -0800 In-Reply-To: <6991885b.050a0220.340abe.02ef.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <699218f3.050a0220.2757fb.0033.GAE@google.com> Subject: Re: [syzbot] [kernel?] KMSAN: uninit-value in __flush_smp_call_function_queue From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: ca4ee40bf13d Partly revert "drm/hyperv: Remove reference t.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=177aec02580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4b4f2aab682301f1 dashboard link: https://syzkaller.appspot.com/bug?extid=4b1bd55fba6260160779 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=120fc722580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10faec02580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/68f5e4558a91/disk-ca4ee40b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ea1eab60444d/vmlinux-ca4ee40b.xz kernel image: https://storage.googleapis.com/syzbot-assets/cc7e3debdec4/bzImage-ca4ee40b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4b1bd55fba6260160779@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: uninit-value in __flush_smp_call_function_queue+0x362/0x18e0 kernel/smp.c:535 __flush_smp_call_function_queue+0x362/0x18e0 kernel/smp.c:535 generic_smp_call_function_single_interrupt+0x1c/0x30 kernel/smp.c:463 __sysvec_call_function_single+0x4b/0x3e0 arch/x86/kernel/smp.c:271 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0x7c/0x90 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1f/0x30 arch/x86/include/asm/idtentry.h:704 native_irq_enable arch/x86/include/asm/irqflags.h:42 [inline] arch_local_irq_enable arch/x86/include/asm/irqflags.h:119 [inline] raw_spin_rq_unlock_irq kernel/sched/sched.h:1629 [inline] finish_lock_switch kernel/sched/core.c:5032 [inline] finish_task_switch+0x11b/0x8b0 kernel/sched/core.c:5150 context_switch kernel/sched/core.c:5298 [inline] __schedule+0x273e/0x8650 kernel/sched/core.c:6907 schedule_idle+0x5a/0x90 kernel/sched/core.c:7030 do_idle+0x748/0x760 kernel/sched/idle.c:360 cpu_startup_entry+0x5f/0x80 kernel/sched/idle.c:430 start_secondary+0xcc/0xd0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147 Local variable reuse.i created at: mas_wr_node_store lib/maple_tree.c:3495 [inline] mas_wr_store_entry+0x14bd/0x96d0 lib/maple_tree.c:3764 mas_store_prealloc+0x1834/0x1e60 lib/maple_tree.c:5169 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ===================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.