I updated one of my old laptops (ECS Desknote 532 with Transmeta CPU) to newest kernel (4.20.0-rc3-00145-gedeca3a769ad) and turned on UBSAN checks. Got the following UBSAN warning multiple times per boot.
The soundcard: 00:04.0 Multimedia audio controller [0401]: ULi Electronics Inc. M5455 PCI AC-Link Controller Audio Device [10b9:5455] (rev 10) Subsystem: Elitegroup Computer Systems M5455 PCI AC-Link Controller Audio Device [1019:0f56] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 64 (16000ns min), Cache Line Size: 128 bytes Interrupt: pin A routed to IRQ 5 Region 0: I/O ports at e400 [size=256] Region 1: Memory at febfe000 (32-bit, non-prefetchable) [size=4K] Capabilities: <access denied> Kernel driver in use: snd_intel8x0 Kernel modules: snd_intel8x0
/proc/asound/cards:
0 [M5455 ]: ICH - ALi M5455 ALi M5455 with ALC655 at irq 5
gcc version 8.2.0 (Debian 8.2.0-9)
[ 15.688683] snd_intel8x0 0000:00:04.0: intel8x0_measure_ac97_clock: measured 58318 usecs (2808 samples) [ 15.689033] snd_intel8x0 0000:00:04.0: clocking to 48000 ... [ 19.667746] ================================================================================ [ 19.668078] UBSAN: Undefined behaviour in sound/pci/ac97/ac97_codec.c:836:7 [ 19.668268] shift exponent 68 is too large for 32-bit type 'int' [ 19.668465] CPU: 0 PID: 199 Comm: alsactl Not tainted 4.20.0-rc3-00145-gedeca3a769ad #2 [ 19.668602] Hardware name: Elitegroup Co. 532/532, BIOS 080010 02/22/2005 [ 19.668602] Call Trace: [ 19.668602] dump_stack+0x16/0x19 [ 19.668602] ubsan_epilogue+0xb/0x29 [ 19.668602] __ubsan_handle_shift_out_of_bounds.cold.15+0x26/0x78 [ 19.668602] snd_ac97_put_spsa.cold.50+0xf/0x24 [snd_ac97_codec] [ 19.668602] ? _copy_from_user+0x33/0xd0 [ 19.668602] snd_ctl_ioctl+0x69e/0x820 [ 19.668602] ? __seccomp_filter+0x60/0x320 [ 19.668602] ? snd_ctl_elem_add_user+0x8a0/0x8a0 [ 19.668602] do_vfs_ioctl+0x90/0x6c0 [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __switch_to_asm+0x32/0x4c [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __switch_to_asm+0x32/0x4c [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __switch_to_asm+0x32/0x4c [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __switch_to_asm+0x32/0x4c [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ? __secure_computing+0x2b/0x80 [ 19.668602] ? syscall_trace_enter+0x141/0x1b0 [ 19.668602] ? __switch_to_asm+0x26/0x4c [ 19.668602] ksys_ioctl+0x39/0x70 [ 19.668602] sys_ioctl+0x11/0x13 [ 19.668602] do_fast_syscall_32+0x90/0x1c0 [ 19.668602] entry_SYSENTER_32+0x6b/0xbd [ 19.668602] EIP: 0xb7fd69ad [ 19.668602] Code: 54 cd ff ff 85 d2 8b 98 58 cd ff ff 89 c8 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76 [ 19.668602] EAX: ffffffda EBX: 00000003 ECX: c2c45513 EDX: bffff670 [ 19.668602] ESI: 00000000 EDI: 00000001 EBP: bffff9c8 ESP: bffff508 [ 19.668602] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000292 [ 19.668602] ================================================================================