I am seeing the following UBSAN warning on three of my computers (4.6.0 with UBSAN turned on). I am reporting this because some of the UBSAN reports have been correct (some have been false positives though).
[ 9.372287] ================================================================================ [ 9.372423] UBSAN: Undefined behaviour in drivers/gpu/drm/radeon/r100.c:595:15 [ 9.372559] shift exponent 255 is too large for 32-bit type 'int' [ 9.372696] CPU: 0 PID: 222 Comm: systemd-udevd Not tainted 4.6.0 #129 [ 9.372831] Hardware name: MicroLink /D850MV , BIOS MV85010A.86A.0067.P24.0304081124 04/08/2003 [ 9.373058] 00000000 c12244c8 f8df9704 c1224aa4 f8df96d4 00000001 00000202 00353532 [ 9.373516] 00000236 00000246 00000246 00000006 00000000 00010246 0000001c 00000006 [ 9.373972] c17f6842 00000031 c1074ab1 00000000 00000000 00000246 00000002 f4a06800 [ 9.374427] Call Trace: [ 9.374567] [<c12244c8>] ? ubsan_epilogue+0x8/0x23 [ 9.374704] [<c1224aa4>] ? __ubsan_handle_shift_out_of_bounds+0xd5/0xdd [ 9.374843] [<c1074ab1>] ? vprintk_emit+0x37a/0x390 [ 9.375156] [<f8ce6bac>] ? r100_hpd_init+0x72/0xb7 [radeon] [ 9.375437] [<f8cdb105>] ? radeon_modeset_init+0x753/0xe7b [radeon] [ 9.375719] [<f8cb044e>] ? radeon_driver_load_kms+0xd8/0x196 [radeon] [ 9.375884] [<f8891eee>] ? drm_dev_register+0x75/0xad [drm] [ 9.376041] [<f88948f1>] ? drm_get_pci_dev+0x11d/0x23e [drm] [ 9.376135] [<c12306b2>] ? pci_device_probe+0x9f/0xee [ 9.376135] [<c12bfb7c>] ? driver_probe_device+0x149/0x271 [ 9.376135] [<c12bfd2a>] ? __driver_attach+0x86/0xa1 [ 9.376135] [<c12bdea0>] ? bus_for_each_dev+0x47/0x5a [ 9.376135] [<c12bf3f7>] ? driver_attach+0x24/0x27 [ 9.376135] [<c12bfca4>] ? driver_probe_device+0x271/0x271 [ 9.376135] [<c12bf111>] ? bus_add_driver+0xed/0x1db [ 9.376135] [<f8e58000>] ? 0xf8e58000 [ 9.376135] [<c12c0603>] ? driver_register+0x9a/0xcb [ 9.376135] [<c10004c1>] ? do_one_initcall+0x159/0x1d9 [ 9.376135] [<c10b25d4>] ? __free_one_page+0x1a1/0x369 [ 9.376135] [<c10e4e66>] ? kernel_poison_pages+0x10/0xc4 [ 9.376135] [<c10b1e8e>] ? free_pages_prepare+0x1f7/0x21c [ 9.376135] [<c10e82e2>] ? kmem_cache_alloc+0xa2/0xd6 [ 9.376135] [<c10abbe7>] ? do_init_module+0x17/0x21a [ 9.376135] [<c10abc46>] ? do_init_module+0x76/0x21a [ 9.376135] [<c109768a>] ? load_module+0x1b28/0x206a [ 9.376135] [<c1097ced>] ? SyS_finit_module+0x71/0x79 [ 9.376135] [<c100169f>] ? do_fast_syscall_32+0xd9/0x111 [ 9.376135] [<c13ebad7>] ? sysenter_past_esp+0x40/0x6a [ 9.376135] ================================================================================