======================================
| [   13.930121][  T248] ==================================================================
| [ 13.930421][ T248] BUG: KASAN: slab-use-after-free in emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
| [   13.930685][  T248] Read of size 1 at addr ffff88800192c720 by task modprobe/248
| [   13.930959][  T248]
[   13.931065][  T248] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.931067][  T248] Call Trace:
[   13.931069][  T248]  <TASK>
[ 13.931071][ T248] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.931082][ T248] print_address_description.constprop.0 (mm/kasan/report.c:409) 
[ 13.931091][ T248] ? emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931094][ T248] print_report (mm/kasan/report.c:522) 
[ 13.931097][ T248] ? emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931099][ T248] ? kasan_addr_to_slab (./include/linux/mm.h:1178 mm/kasan/../slab.h:211 mm/kasan/common.c:38) 
[ 13.931102][ T248] ? emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931105][ T248] kasan_report (mm/kasan/report.c:636) 
[ 13.931109][ T248] ? emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931113][ T248] ? emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931116][ T248] __kasan_check_byte (mm/kasan/common.c:561) 
[ 13.931119][ T248] krealloc_noprof (mm/slub.c:4858 mm/slub.c:4958) 
[ 13.931124][ T248] ? execmem_alloc (mm/execmem.c:299 mm/execmem.c:383) 
[ 13.931131][ T248] emit_its_trampoline (arch/x86/kernel/alternative.c:129 arch/x86/kernel/alternative.c:236 arch/x86/kernel/alternative.c:264 arch/x86/kernel/alternative.c:808) 
[ 13.931133][ T248] ? __x86_indirect_paranoid_thunk_rbx (./arch/x86/include/asm/GEN-for-each-reg.h:9) 
[ 13.931141][ T248] ? __pi___x86_indirect_thunk_rdx (./arch/x86/include/asm/GEN-for-each-reg.h:9) 
[ 13.931145][ T248] apply_retpolines (arch/x86/kernel/alternative.c:994 (discriminator 3)) 
[ 13.931150][ T248] ? __pfx_apply_retpolines (arch/x86/kernel/alternative.c:946) 
[ 13.931153][ T248] ? __pfx___mutex_lock (kernel/locking/mutex.c:746) 
[ 13.931163][ T248] module_finalize (arch/x86/kernel/module.c:292) 
[ 13.931172][ T248] ? add_kallsyms (kernel/module/kallsyms.c:212) 
[ 13.931178][ T248] ? __pfx_module_finalize (arch/x86/kernel/module.c:241) 
[ 13.931183][ T248] ? __pfx_cmp_ex_sort (lib/extable.c:52) 
[ 13.931186][ T248] ? __pfx_swap_ex (lib/extable.c:28) 
[ 13.931191][ T248] load_module (kernel/module/main.c:2927 kernel/module/main.c:3422) 
[ 13.931200][ T248] ? __pfx_load_module (kernel/module/main.c:3327) 
[ 13.931203][ T248] ? kernel_read_file (fs/kernel_read_file.c:80 (discriminator 2)) 
[ 13.931210][ T248] ? kernel_read_file (./arch/x86/include/asm/atomic.h:53 ./include/linux/atomic/atomic-arch-fallback.h:992 ./include/linux/atomic/atomic-instrumented.h:436 ./include/linux/fs.h:3192 fs/kernel_read_file.c:122) 
[ 13.931214][ T248] ? __pfx_kernel_read_file (fs/kernel_read_file.c:38) 
[ 13.931217][ T248] ? add_chain_cache (kernel/locking/lockdep.c:3770) 
[ 13.931224][ T248] ? init_module_from_file (kernel/module/main.c:3673) 
[ 13.931227][ T248] init_module_from_file (kernel/module/main.c:3673) 
[ 13.931231][ T248] ? __pfx_init_module_from_file (kernel/module/main.c:3649) 
[ 13.931240][ T248] ? idempotent_init_module (kernel/module/main.c:3685) 
[ 13.931243][ T248] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.931249][ T248] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 13.931253][ T248] idempotent_init_module (kernel/module/main.c:3685) 
[ 13.931258][ T248] ? __pfx_idempotent_init_module (kernel/module/main.c:3677) 
[ 13.931265][ T248] ? cap_capable (security/commoncap.c:132) 
[ 13.931274][ T248] __x64_sys_finit_module (./include/linux/file.h:62 ./include/linux/file.h:83 kernel/module/main.c:3708 kernel/module/main.c:3695 kernel/module/main.c:3695) 
[ 13.931277][ T248] ? do_syscall_64 (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:119 ./include/linux/entry-common.h:199 arch/x86/entry/syscall_64.c:90) 
[ 13.931282][ T248] do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) 
[ 13.931285][ T248] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   13.931290][  T248] RIP: 0033:0x7f252b0f1e5d
[ 13.931294][ T248] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
All code
========
   0:	ff c3                	inc    %ebx
   2:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   9:	00 00 00 
   c:	90                   	nop
   d:	f3 0f 1e fa          	endbr64
  11:	48 89 f8             	mov    %rdi,%rax
  14:	48 89 f7             	mov    %rsi,%rdi
  17:	48 89 d6             	mov    %rdx,%rsi
  1a:	48 89 ca             	mov    %rcx,%rdx
  1d:	4d 89 c2             	mov    %r8,%r10
  20:	4d 89 c8             	mov    %r9,%r8
  23:	4c 8b 4c 24 08       	mov    0x8(%rsp),%r9
  28:	0f 05                	syscall
  2a:*	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax		<-- trapping instruction
  30:	73 01                	jae    0x33
  32:	c3                   	ret
  33:	48 8b 0d 73 9f 1b 00 	mov    0x1b9f73(%rip),%rcx        # 0x1b9fad
  3a:	f7 d8                	neg    %eax
  3c:	64 89 01             	mov    %eax,%fs:(%rcx)
  3f:	48                   	rex.W

Code starting with the faulting instruction
===========================================
   0:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   6:	73 01                	jae    0x9
   8:	c3                   	ret
   9:	48 8b 0d 73 9f 1b 00 	mov    0x1b9f73(%rip),%rcx        # 0x1b9f83
  10:	f7 d8                	neg    %eax
  12:	64 89 01             	mov    %eax,%fs:(%rcx)
  15:	48                   	rex.W
[   13.931297][  T248] RSP: 002b:00007ffe23c94348 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   13.931301][  T248] RAX: ffffffffffffffda RBX: 000055e57e83b960 RCX: 00007f252b0f1e5d
[   13.931303][  T248] RDX: 0000000000000000 RSI: 000055e5744c1a2a RDI: 0000000000000005
[   13.931305][  T248] RBP: 0000000000040000 R08: 0000000000000000 R09: 00007ffe23c94480
[   13.931307][  T248] R10: 0000000000000005 R11: 0000000000000246 R12: 000055e5744c1a2a


Finger prints:
print_report:kasan_report:__kasan_check_byte:krealloc_noprof:emit_its_trampoline