================================================================== BUG: KMSAN: uninit-value in capi_write+0x791/0xa90 drivers/isdn/capi/capi.c:700 CPU: 1 PID: 23128 Comm: syz-executor5 Not tainted 4.20.0-rc7+ #1 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+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613 __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313 capi_write+0x791/0xa90 drivers/isdn/capi/capi.c:700 __vfs_write+0x1f4/0xb70 fs/read_write.c:485 vfs_write+0x478/0x8d0 fs/read_write.c:549 ksys_write fs/read_write.c:598 [inline] __do_sys_write fs/read_write.c:610 [inline] __se_sys_write+0x17a/0x370 fs/read_write.c:607 __x64_sys_write+0x4a/0x70 fs/read_write.c:607 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc5716dbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc5716dc6d4 R13: 00000000004c6bbb R14: 00000000004dbe78 R15: 00000000ffffffff Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline] kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185 slab_post_alloc_hook mm/slab.h:446 [inline] slab_alloc_node mm/slub.c:2759 [inline] __kmalloc_node_track_caller+0xe18/0x1030 mm/slub.c:4383 __kmalloc_reserve net/core/skbuff.c:137 [inline] __alloc_skb+0x309/0xa20 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:998 [inline] capi_write+0x12f/0xa90 drivers/isdn/capi/capi.c:691 __vfs_write+0x1f4/0xb70 fs/read_write.c:485 vfs_write+0x478/0x8d0 fs/read_write.c:549 ksys_write fs/read_write.c:598 [inline] __do_sys_write fs/read_write.c:610 [inline] __se_sys_write+0x17a/0x370 fs/read_write.c:607 __x64_sys_write+0x4a/0x70 fs/read_write.c:607 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 ==================================================================