Hello,On Mon, 27 Apr 2026, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: e728258debd5 Merge tag 'net-7.1-rc1' of git://git.kernel.o.. > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=169022ce580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ca77bfc4078c8193 > dashboard link: https://syzkaller.appspot.com/bug?extid=217f1db9c791e27fe54a > compiler: Debian clang version 21.1.8 > (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: > https://storage.googleapis.com/syzbot-assets/24195bde5d1d/disk-e728258d.raw.xz > vmlinux: > https://storage.googleapis.com/syzbot-assets/78131d1b0e14/vmlinux-e728258d.xz > kernel image: > https://storage.googleapis.com/syzbot-assets/836d0dd78c10/bzImage-e728258d.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: [email protected] > > wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same > SSID (merge) > ------------[ cut here ]------------ > UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13 > shift exponent 64 is too large for 64-bit type 'unsigned long' > CPU: 1 UID: 0 PID: 77 Comm: kworker/u8:4 Not tainted syzkaller #0 > PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 04/18/2026 > Workqueue: events_unbound conn_resize_work_handler > Call Trace: > <TASK> > dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 > ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 > __ubsan_handle_shift_out_of_bounds+0x385/0x410 lib/ubsan.c:494 > __roundup_pow_of_two include/linux/log2.h:57 [inline] Looks like roundup_pow_of_two() is called for 0. Will provide fix for this... > ip_vs_rht_desired_size+0x2cf/0x410 net/netfilter/ipvs/ip_vs_core.c:240 > ip_vs_conn_desired_size net/netfilter/ipvs/ip_vs_conn.c:765 [inline] > conn_resize_work_handler+0x1b6/0x14c0 net/netfilter/ipvs/ip_vs_conn.c:822 > process_one_work kernel/workqueue.c:3302 [inline] > process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 > worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 > kthread+0x388/0x470 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > </TASK> > ---[ end trace ]--- > Kernel panic - not syncing: UBSAN: panic_on_warn set ... > CPU: 1 UID: 0 PID: 77 Comm: kworker/u8:4 Not tainted syzkaller #0 > PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 04/18/2026 > Workqueue: events_unbound conn_resize_work_handler > Call Trace: > <TASK> > vpanic+0x56c/0xa60 kernel/panic.c:650 > panic+0xc5/0xd0 kernel/panic.c:787 > check_panic_on_warn+0x89/0xb0 kernel/panic.c:524 > __ubsan_handle_shift_out_of_bounds+0x385/0x410 lib/ubsan.c:494 > __roundup_pow_of_two include/linux/log2.h:57 [inline] > ip_vs_rht_desired_size+0x2cf/0x410 net/netfilter/ipvs/ip_vs_core.c:240 > ip_vs_conn_desired_size net/netfilter/ipvs/ip_vs_conn.c:765 [inline] > conn_resize_work_handler+0x1b6/0x14c0 net/netfilter/ipvs/ip_vs_conn.c:822 > process_one_work kernel/workqueue.c:3302 [inline] > process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 > worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 > kthread+0x388/0x470 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > </TASK> > Kernel Offset: disabled > Rebooting in 86400 seconds.. Regards -- Julian Anastasov <[email protected]>
