Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 39ec47bbfd5dd3cea0b711ee9f1acdca37399c86 ("[PATCH v2 2/7] drm/selftests: add drm buddy alloc limit testcase") url: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith ub.com%2F0day-ci%2Flinux%2Fcommits%2FArunpravin%2Fdrm-selftests-Move-i 915-buddy-selftests-into-drm%2F20220223-015043&amp;data=04%7C01%7Cchri stian.koenig%40amd.com%7C3101ff318a994e6eaf5f08d9fa0481ea%7C3dd8961fe4 884e608e11a82d994e183d%7C0%7C0%7C637815719552700496%7CUnknown%7CTWFpbG Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0% 3D%7C3000&amp;sdata=sKvsDtHufRMfSO14HdmHxvNsJiPyDZVDXCFUpWTDwFI%3D&amp ;reserved=0 patch link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore .kernel.org%2Fdri-devel%2F20220222174845.2175-2-Arunpravin.PaneerSelva m%40amd.com&amp;data=04%7C01%7Cchristian.koenig%40amd.com%7C3101ff318a 994e6eaf5f08d9fa0481ea%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C63 7815719552700496%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV 2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=aWG4x27aMLcOySO UkHbLQ1NL9L8t8AF4dgXux65IIP8%3D&amp;reserved=0 in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu Icelake-Server -smp 4 -m 16G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +---------------------------------------------------+------------+------------+ | | be9e8c6c00 | | 39ec47bbfd | +---------------------------------------------------+------------+------------+ | boot_successes | 14 | 0 | | boot_failures | 0 | 16 | | UBSAN:shift-out-of-bounds_in_include/linux/log2.h | 0 | 16 | | kernel_BUG_at_drivers/gpu/drm/drm_buddy.c | 0 | 16 | | invalid_opcode:#[##] | 0 | 16 | | EIP:drm_buddy_init | 0 | 16 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 16 | +---------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <oliver.sang(a)intel.com&gt; [ 68.124177][ T1] UBSAN: shift-out-of-bounds in include/linux/log2.h:67:13 [ 68.125333][ T1] shift exponent 4294967295 is too large for 32-bit type 'long unsigned int' [ 68.126563][ T1] CPU: 0 PID: 1 Comm: swapper Not tainted 5.17.0-rc2-00311-g39ec47bbfd5d #2 [ 68.127758][ T1] Call Trace: [ 68.128187][ T1] dump_stack_lvl (lib/dump_stack.c:108) [ 68.128793][ T1] dump_stack (lib/dump_stack.c:114) [ 68.129331][ T1] ubsan_epilogue (lib/ubsan.c:152) [ 68.129958][ T1] __ubsan_handle_shift_out_of_bounds.cold (arch/x86/include/asm/smap.h:85) [ 68.130791][ T1] ? drm_block_alloc+0x28/0x80 [ 68.131582][ T1] ? rcu_read_lock_sched_held (kernel/rcu/update.c:125) [ 68.132215][ T1] ? kmem_cache_alloc (include/trace/events/kmem.h:54 mm/slab.c:3501) [ 68.132878][ T1] ? mark_free+0x2e/0x80 [ 68.133524][ T1] drm_buddy_init.cold (include/linux/log2.h:67 drivers/gpu/drm/drm_buddy.c:131) [ 68.134145][ T1] ? test_drm_cmdline_init (drivers/gpu/drm/selftests/test-drm_buddy.c:87) [ 68.134770][ T1] igt_buddy_alloc_limit (drivers/gpu/drm/selftests/test-drm_buddy.c:30) [ 68.135472][ T1] ? vprintk_default (kernel/printk/printk.c:2257) [ 68.136057][ T1] ? test_drm_cmdline_init (drivers/gpu/drm/selftests/test-drm_buddy.c:87) [ 68.136812][ T1] test_drm_buddy_init (drivers/gpu/drm/selftests/drm_selftest.c:77 drivers/gpu/drm/selftests/test-drm_buddy.c:95) [ 68.137475][ T1] do_one_initcall (init/main.c:1300) [ 68.138111][ T1] ? parse_args (kernel/params.c:609 kernel/params.c:146 kernel/params.c:188) [ 68.138717][ T1] do_basic_setup (init/main.c:1372 init/main.c:1389 init/main.c:1408) [ 68.139366][ T1] kernel_init_freeable (init/main.c:1617) [ 68.140040][ T1] ? rest_init (init/main.c:1494) [ 68.140634][ T1] kernel_init (init/main.c:1504) [ 68.141155][ T1] ret_from_fork (arch/x86/entry/entry_32.S:772) [ 68.141607][ T1] ================================================================================ [ 68.146730][ T1] ------------[ cut here ]------------ [ 68.147460][ T1] kernel BUG at drivers/gpu/drm/drm_buddy.c:140! [ 68.148280][ T1] invalid opcode: 0000 [#1] [ 68.148895][ T1] CPU: 0 PID: 1 Comm: swapper Not tainted 5.17.0-rc2-00311-g39ec47bbfd5d #2 [ 68.149896][ T1] EIP: drm_buddy_init (drivers/gpu/drm/drm_buddy.c:140 (discriminator 1)) [ 68.149896][ T1] Code: 76 00 b8 ea ff ff ff 8d 65 f4 5b 5e 5f 5d c3 8d 76 00 0f bd 45 d8 75 05 b8 ff ff ff ff 83 c0 21 e9 5e ff ff ff 8d 74 26 00 90 <0f> 0b 8d b6 00 00 00 00 0f 0b 8d b6 00 00 00 00 8b 5d 0c 0f bd 45 All code ======== 0: 76 00 jbe 0x2 2: b8 ea ff ff ff mov $0xffffffea,%eax 7: 8d 65 f4 lea -0xc(%rbp),%esp a: 5b pop %rbx b: 5e pop %rsi c: 5f pop %rdi d: 5d pop %rbp e: c3 retq f: 8d 76 00 lea 0x0(%rsi),%esi 12: 0f bd 45 d8 bsr -0x28(%rbp),%eax 16: 75 05 jne 0x1d 18: b8 ff ff ff ff mov $0xffffffff,%eax 1d: 83 c0 21 add $0x21,%eax 20: e9 5e ff ff ff jmpq 0xffffffffffffff83 25: 8d 74 26 00 lea 0x0(%rsi,%riz,1),%esi 29: 90 nop 2a:* 0f 0b ud2 <-- trapping instruction 2c: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 32: 0f 0b ud2 34: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 3a: 8b 5d 0c mov 0xc(%rbp),%ebx 3d: 0f .byte 0xf 3e: bd .byte 0xbd 3f: 45 rex.RB Code starting with the faulting instruction =========================================== 0: 0f 0b ud2 2: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 8: 0f 0b ud2 a: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 10: 8b 5d 0c mov 0xc(%rbp),%ebx 13: 0f .byte 0xf 14: bd .byte 0xbd 15: 45 rex.RB [ 68.149896][ T1] EAX: 8578e658 EBX: 8578e618 ECX: 8578e658 EDX: 83717c98 [ 68.149896][ T1] ESI: 83675ee0 EDI: 00000034 EBP: 83675ec0 ESP: 83675e94 [ 68.149896][ T1] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010297 [ 68.149896][ T1] CR0: 80050033 CR2: 77f35844 CR3: 02a10000 CR4: 00150ed0 [ 68.149896][ T1] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 68.149896][ T1] DR6: fffe0ff0 DR7: 00000400 [ 68.149896][ T1] Call Trace: [ 68.149896][ T1] ? test_drm_cmdline_init (drivers/gpu/drm/selftests/test-drm_buddy.c:87) [ 68.149896][ T1] igt_buddy_alloc_limit (drivers/gpu/drm/selftests/test-drm_buddy.c:30) [ 68.149896][ T1] ? vprintk_default (kernel/printk/printk.c:2257) [ 68.149896][ T1] ? test_drm_cmdline_init (drivers/gpu/drm/selftests/test-drm_buddy.c:87) [ 68.149896][ T1] test_drm_buddy_init (drivers/gpu/drm/selftests/drm_selftest.c:77 drivers/gpu/drm/selftests/test-drm_buddy.c:95) [ 68.149896][ T1] do_one_initcall (init/main.c:1300) [ 68.149896][ T1] ? parse_args (kernel/params.c:609 kernel/params.c:146 kernel/params.c:188) [ 68.149896][ T1] do_basic_setup (init/main.c:1372 init/main.c:1389 init/main.c:1408) [ 68.149896][ T1] kernel_init_freeable (init/main.c:1617) [ 68.149896][ T1] ? rest_init (init/main.c:1494) [ 68.149896][ T1] kernel_init (init/main.c:1504) [ 68.149896][ T1] ret_from_fork (arch/x86/entry/entry_32.S:772) [ 68.149896][ T1] Modules linked in: [ 68.167316][ T1] ---[ end trace 0000000000000000 ]--- [ 68.168062][ T1] EIP: drm_buddy_init (drivers/gpu/drm/drm_buddy.c:140 (discriminator 1)) [ 68.168739][ T1] Code: 76 00 b8 ea ff ff ff 8d 65 f4 5b 5e 5f 5d c3 8d 76 00 0f bd 45 d8 75 05 b8 ff ff ff ff 83 c0 21 e9 5e ff ff ff 8d 74 26 00 90 <0f> 0b 8d b6 00 00 00 00 0f 0b 8d b6 00 00 00 00 8b 5d 0c 0f bd 45 All code ======== 0: 76 00 jbe 0x2 2: b8 ea ff ff ff mov $0xffffffea,%eax 7: 8d 65 f4 lea -0xc(%rbp),%esp a: 5b pop %rbx b: 5e pop %rsi c: 5f pop %rdi d: 5d pop %rbp e: c3 retq f: 8d 76 00 lea 0x0(%rsi),%esi 12: 0f bd 45 d8 bsr -0x28(%rbp),%eax 16: 75 05 jne 0x1d 18: b8 ff ff ff ff mov $0xffffffff,%eax 1d: 83 c0 21 add $0x21,%eax 20: e9 5e ff ff ff jmpq 0xffffffffffffff83 25: 8d 74 26 00 lea 0x0(%rsi,%riz,1),%esi 29: 90 nop 2a:* 0f 0b ud2 <-- trapping instruction 2c: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 32: 0f 0b ud2 34: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 3a: 8b 5d 0c mov 0xc(%rbp),%ebx 3d: 0f .byte 0xf 3e: bd .byte 0xbd 3f: 45 rex.RB Code starting with the faulting instruction =========================================== 0: 0f 0b ud2 2: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 8: 0f 0b ud2 a: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 10: 8b 5d 0c mov 0xc(%rbp),%ebx 13: 0f .byte 0xf 14: bd .byte 0xbd 15: 45 rex.RB To reproduce: # build kernel cd linux cp config-5.17.0-rc2-00311-g39ec47bbfd5d .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 INSTALL_MOD_PATH=<mod-install-dir> modules_install cd <mod-install-dir> find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz git clone https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.... cd lkp-tests bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email # if come across any failure that blocks the test, # please remove ~/.lkp and /lkp dir to run from a clean state. --- 0DAY/LKP+ Test Infrastructure Open Source Technology Center https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.0... Intel Corporation Thanks, Oliver Sang