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BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
CPU: 0 PID: 26805 Comm: syz-executor.5 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
 kmsan_internal_check_memory+0x358/0x3d0 mm/kmsan/kmsan.c:457
 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
 instrument_copy_to_user include/linux/instrumented.h:91 [inline]
 _copy_to_user+0x18e/0x260 lib/usercopy.c:30
 copy_to_user include/linux/uaccess.h:161 [inline]
 fb_read+0xa30/0xcf0 drivers/video/fbdev/core/fbmem.c:812
 do_loop_readv_writev fs/read_write.c:734 [inline]
 do_iter_read+0xa95/0x1020 fs/read_write.c:955
 compat_readv fs/read_write.c:1262 [inline]
 do_compat_readv fs/read_write.c:1282 [inline]
 __do_compat_sys_readv fs/read_write.c:1294 [inline]
 __se_compat_sys_readv+0x2d8/0x6c0 fs/read_write.c:1290
 __ia32_compat_sys_readv+0x4a/0x70 fs/read_write.c:1290
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2af/0x480 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fd6549
Code: Bad RIP value.
RSP: 002b:00000000f55d00cc EFLAGS: 00000296 ORIG_RAX: 0000000000000091
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000140
RDX: 0000000000000002 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:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 slab_alloc mm/slub.c:2848 [inline]
 __kmalloc+0x312/0x410 mm/slub.c:3911
 kmalloc include/linux/slab.h:560 [inline]
 fb_read+0x71a/0xcf0 drivers/video/fbdev/core/fbmem.c:795
 do_loop_readv_writev fs/read_write.c:734 [inline]
 do_iter_read+0xa95/0x1020 fs/read_write.c:955
 compat_readv fs/read_write.c:1262 [inline]
 do_compat_readv fs/read_write.c:1282 [inline]
 __do_compat_sys_readv fs/read_write.c:1294 [inline]
 __se_compat_sys_readv+0x2d8/0x6c0 fs/read_write.c:1290
 __ia32_compat_sys_readv+0x4a/0x70 fs/read_write.c:1290
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2af/0x480 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Bytes 0-30 of 31 are uninitialized
Memory access of size 31 starts at ffff888107623400
Data copied to user address 0000000020000080
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