======================================
| [   30.848043][  T474] ==================================================================
| [ 30.848351][ T474] 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) 
| [   30.848607][  T474] Read of size 1 at addr ffff88800193b720 by task modprobe/474
| [   30.848857][  T474]
[   30.848952][  T474] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   30.848955][  T474] Call Trace:
[   30.848957][  T474]  <TASK>
[ 30.848959][ T474] dump_stack_lvl (lib/dump_stack.c:123) 
[ 30.848966][ T474] print_address_description.constprop.0 (mm/kasan/report.c:409) 
[ 30.848972][ T474] ? 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) 
[ 30.848976][ T474] print_report (mm/kasan/report.c:522) 
[ 30.848979][ T474] ? 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) 
[ 30.848982][ T474] ? kasan_addr_to_slab (./include/linux/mm.h:1178 mm/kasan/../slab.h:211 mm/kasan/common.c:38) 
[ 30.848985][ T474] ? 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) 
[ 30.848988][ T474] kasan_report (mm/kasan/report.c:636) 
[ 30.848992][ T474] ? 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) 
[ 30.848996][ T474] ? 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) 
[ 30.848999][ T474] __kasan_check_byte (mm/kasan/common.c:561) 
[ 30.849003][ T474] krealloc_noprof (mm/slub.c:4858 mm/slub.c:4958) 
[ 30.849007][ T474] ? execmem_alloc (mm/execmem.c:299 mm/execmem.c:383) 
[ 30.849012][ T474] 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) 
[ 30.849015][ T474] ? __x86_indirect_paranoid_thunk_rcx (./arch/x86/include/asm/GEN-for-each-reg.h:7) 
[ 30.849020][ T474] ? __pi___x86_indirect_thunk_rax (./arch/x86/include/asm/GEN-for-each-reg.h:7) 
[ 30.849026][ T474] apply_retpolines (arch/x86/kernel/alternative.c:994 (discriminator 3)) 
[ 30.849029][ T474] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 30.849033][ T474] ? __pfx_apply_retpolines (arch/x86/kernel/alternative.c:946) 
[ 30.849037][ T474] ? __pfx___mutex_lock (kernel/locking/mutex.c:746) 
[ 30.849045][ T474] ? memcmp (lib/string.c:694) 
[ 30.849052][ T474] module_finalize (arch/x86/kernel/module.c:292) 
[ 30.849059][ T474] ? add_kallsyms (kernel/module/kallsyms.c:212) 
[ 30.849063][ T474] ? __pfx_module_finalize (arch/x86/kernel/module.c:241) 
[ 30.849067][ T474] ? __pfx_cmp_ex_sort (lib/extable.c:52) 
[ 30.849070][ T474] ? __pfx_swap_ex (lib/extable.c:28) 
[ 30.849074][ T474] load_module (kernel/module/main.c:2927 kernel/module/main.c:3422) 
[ 30.849080][ T474] ? __pfx_load_module (kernel/module/main.c:3327) 
[ 30.849083][ T474] ? kernel_read_file (fs/kernel_read_file.c:80 (discriminator 2)) 
[ 30.849089][ T474] ? 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) 
[ 30.849092][ T474] ? __pfx_kernel_read_file (fs/kernel_read_file.c:38) 
[ 30.849096][ T474] ? add_chain_cache (kernel/locking/lockdep.c:3770) 
[ 30.849101][ T474] ? init_module_from_file (kernel/module/main.c:3673) 
[ 30.849104][ T474] init_module_from_file (kernel/module/main.c:3673) 
[ 30.849107][ T474] ? __pfx_init_module_from_file (kernel/module/main.c:3649) 
[ 30.849115][ T474] ? idempotent_init_module (kernel/module/main.c:3685) 
[ 30.849117][ T474] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 30.849121][ T474] ? 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) 
[ 30.849126][ T474] idempotent_init_module (kernel/module/main.c:3685) 
[ 30.849130][ T474] ? __pfx_idempotent_init_module (kernel/module/main.c:3677) 
[ 30.849137][ T474] ? cap_capable (security/commoncap.c:132) 
[ 30.849143][ T474] __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) 
[ 30.849146][ T474] ? 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) 
[ 30.849150][ T474] do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) 
[ 30.849154][ T474] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   30.849158][  T474] RIP: 0033:0x7f65999b2e5d
[ 30.849163][ T474] 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
[   30.849165][  T474] RSP: 002b:00007ffe2eb0b9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   30.849169][  T474] RAX: ffffffffffffffda RBX: 00005590c11c8960 RCX: 00007f65999b2e5d
[   30.849171][  T474] RDX: 0000000000000000 RSI: 00005590a62aba2a RDI: 0000000000000005
[   30.849173][  T474] RBP: 0000000000040000 R08: 0000000000000000 R09: 00007ffe2eb0bb30
[   30.849175][  T474] R10: 0000000000000005 R11: 0000000000000246 R12: 00005590a62aba2a


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