===================================================== BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 CPU: 1 PID: 13499 Comm: syz-executor.3 Not tainted 5.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x24c/0x2e0 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x469/0x500 mm/kmsan/kmsan.c:433 kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 instrument_copy_to_user include/linux/instrumented.h:121 [inline] _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 copy_to_user include/linux/uaccess.h:209 [inline] fb_cmap_to_user+0x40a/0x990 drivers/video/fbdev/core/fbcmap.c:208 fb_getput_cmap drivers/video/fbdev/core/fbmem.c:1241 [inline] fb_compat_ioctl+0x877/0x1780 drivers/video/fbdev/core/fbmem.c:1318 __do_compat_sys_ioctl fs/ioctl.c:842 [inline] __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] __do_fast_syscall_32+0x127/0x180 arch/x86/entry/common.c:142 do_fast_syscall_32+0x77/0xd0 arch/x86/entry/common.c:168 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:211 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f0b549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f55055fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004604 RDX: 0000000020000200 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:120 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:103 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76 slab_alloc_node mm/slub.c:2922 [inline] slab_alloc mm/slub.c:2931 [inline] __kmalloc+0x387/0x550 mm/slub.c:4068 kmalloc include/linux/slab.h:559 [inline] fb_alloc_cmap_gfp+0x39b/0xa70 drivers/video/fbdev/core/fbcmap.c:104 fb_alloc_cmap+0x95/0xb0 drivers/video/fbdev/core/fbcmap.c:135 drm_fb_helper_alloc_fbi+0x106/0x3f0 drivers/gpu/drm/drm_fb_helper.c:563 drm_fb_helper_generic_probe+0x4f3/0xc70 drivers/gpu/drm/drm_fb_helper.c:2330 drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1668 [inline] __drm_fb_helper_initial_config_and_unlock+0x1cac/0x26c0 drivers/gpu/drm/drm_fb_helper.c:1826 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1921 [inline] drm_fbdev_client_hotplug+0xbb8/0xd70 drivers/gpu/drm/drm_fb_helper.c:2423 drm_fbdev_generic_setup+0x39d/0xa00 drivers/gpu/drm/drm_fb_helper.c:2510 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:178 [inline] vkms_init+0x9d6/0xc43 drivers/gpu/drm/vkms/vkms_drv.c:202 do_one_initcall+0x362/0x8d0 init/main.c:1229 do_initcall_level+0x1e7/0x35a init/main.c:1302 do_initcalls+0x127/0x1cb init/main.c:1318 do_basic_setup+0x33/0x36 init/main.c:1338 kernel_init_freeable+0x287/0x3cc init/main.c:1540 kernel_init+0x1f/0x840 init/main.c:1427 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Bytes 0-1 of 2 are uninitialized Memory access of size 2 starts at ffff88810558ca54 Data copied to user address 0000000020000100 =====================================================