Hello,
syzbot found the following issue on:
HEAD commit: ce8056d1 wip: changed copy_from_user where instrumented git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=14dcd116900000 kernel config: https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f dashboard link: https://syzkaller.appspot.com/bug?extid=2741e4d93bff16ad8d4d compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=103f7891900000
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2741e4d93bff16ad8d4d@syzkaller.appspotmail.com
===================================================== BUG: KMSAN: uninit-value in soft_cursor+0xa89/0x13f0 drivers/video/fbdev/core/softcursor.c:61 CPU: 0 PID: 12272 Comm: syz-executor.2 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 soft_cursor+0xa89/0x13f0 drivers/video/fbdev/core/softcursor.c:61 bit_cursor+0x38c6/0x3a40 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x195e/0x1a60 drivers/video/fbdev/core/fbcon.c:1411 set_cursor drivers/tty/vt/vt.c:915 [inline] redraw_screen+0x28ee/0x2980 drivers/tty/vt/vt.c:1031 vc_do_resize+0x36a8/0x38f0 drivers/tty/vt/vt.c:1314 vc_resize+0xc3/0xe0 drivers/tty/vt/vt.c:1334 fbcon_modechanged+0xdc1/0x1320 drivers/video/fbdev/core/fbcon.c:2990 fbcon_update_vcs+0x86/0xa0 drivers/video/fbdev/core/fbcon.c:3048 fb_set_var+0x1420/0x1850 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0xc00/0x1150 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0x1e4/0x210 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl fs/ioctl.c:753 [inline] __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl+0x319/0x4d0 fs/ioctl.c:760 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:760 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d239 Code: Bad RIP value. RSP: 002b:00007ff9aafacc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000d580 RCX: 000000000045d239 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 000000000169fb6f R14: 00007ff9aafad9c0 R15: 000000000118cf4c
Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 soft_cursor+0x44d/0x13f0 drivers/video/fbdev/core/softcursor.c:50 bit_cursor+0x38c6/0x3a40 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x195e/0x1a60 drivers/video/fbdev/core/fbcon.c:1411 set_cursor drivers/tty/vt/vt.c:915 [inline] redraw_screen+0x28ee/0x2980 drivers/tty/vt/vt.c:1031 vc_do_resize+0x36a8/0x38f0 drivers/tty/vt/vt.c:1314 vc_resize+0xc3/0xe0 drivers/tty/vt/vt.c:1334 fbcon_modechanged+0xdc1/0x1320 drivers/video/fbdev/core/fbcon.c:2990 fbcon_update_vcs+0x86/0xa0 drivers/video/fbdev/core/fbcon.c:3048 fb_set_var+0x1420/0x1850 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0xc00/0x1150 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0x1e4/0x210 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl fs/ioctl.c:753 [inline] __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl+0x319/0x4d0 fs/ioctl.c:760 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:760 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Local variable ----cursor@bit_cursor created at: bit_cursor+0xe3/0x3a40 drivers/video/fbdev/core/bitblit.c:239 bit_cursor+0xe3/0x3a40 drivers/video/fbdev/core/bitblit.c:239 =====================================================
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