freebsd boot error: panic: ASan: Invalid access, 1-byte read at ADDR, MallocRedZone(fb)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: da2f833f MMCCAM: fix a panic after cam_sim_alloc_dev() rem..
git tree: https://github.com/freebsd/freebsd-src.git main
console output: https://syzkaller.appspot.com/x/log.txt?x=16018d72300000
dashboard link: https://syzkaller.appspot.com/bug?extid=f256beefd0df9eb796e7

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f256be...@syzkaller.appspotmail.com

panic: ASan: Invalid access, 1-byte read at 0xfffffe0054048253, MallocRedZone(fb)
cpuid = 0
time = 1
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0xc7/frame 0xffffffff84f44ef0
kdb_backtrace() at kdb_backtrace+0xd3/frame 0xffffffff84f45050
vpanic() at vpanic+0x2c5/frame 0xffffffff84f45130
panic() at panic+0xb5/frame 0xffffffff84f45200
__asan_load1_noabort() at __asan_load1_noabort+0x11a/frame 0xffffffff84f452c0
ns8250_bus_probe() at ns8250_bus_probe+0xfc8/frame 0xffffffff84f45340
uart_bus_probe() at uart_bus_probe+0x3d6/frame 0xffffffff84f453d0
uart_acpi_probe() at uart_acpi_probe+0x2f1/frame 0xffffffff84f454c0
device_probe_child() at device_probe_child+0x8c1/frame 0xffffffff84f45560
device_probe() at device_probe+0x16c/frame 0xffffffff84f455b0
device_probe_and_attach() at device_probe_and_attach+0x3b/frame 0xffffffff84f455f0
bus_generic_attach() at bus_generic_attach+0x28/frame 0xffffffff84f45610
acpi_attach() at acpi_attach+0x1ade/frame 0xffffffff84f45810
device_attach() at device_attach+0x6ff/frame 0xffffffff84f45910
device_probe_and_attach() at device_probe_and_attach+0xe3/frame 0xffffffff84f45950
bus_generic_attach() at bus_generic_attach+0x28/frame 0xffffffff84f45970
device_attach() at device_attach+0x6ff/frame 0xffffffff84f45a80
device_probe_and_attach() at device_probe_and_attach+0xe3/frame 0xffffffff84f45ac0
bus_generic_new_pass() at bus_generic_new_pass+0x21e/frame 0xffffffff84f45b10
bus_set_pass() at bus_set_pass+0x12b/frame 0xffffffff84f45b50
configure() at configure+0x10/frame 0xffffffff84f45b70
mi_startup() at mi_startup+0x457/frame 0xffffffff84f45cb0
btext() at btext+0x22
KDB: enter: panic
[ thread pid 0 tid 100000 ]
Stopped at kdb_enter+0x6b: movq $0,0x28f86da(%rip)
db>


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