re: kern/59518: edgeroute 4 asserts every few months

["matthew green via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/59518; it has been noted by GNATS.

From: matthew green <mrg%eterna23.net@localhost>
To: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%netbsd.org@localhost
Cc: 
Subject: re: kern/59518: edgeroute 4 asserts every few months
Date: Tue, 08 Jul 2025 16:32:38 +1000

 i noticed there is some info about the stack i missed before:
 
 db> ps          =
 
 PID     LID S CPU     FLAGS       STRUCT LWP *               NAME WAIT
 11131>11131 7   0     40000   980000004d534e00          makemandb
 ...
 0    >    6 7   0       200   980000004eed7280          softser/0
 
 which gave me two threads to inspect:
 
 db> bt/a 980000004eed7280
 pid 0.6 at 0x98000000001bc000
 0x98000000001bfdc0: kernel_text+0xe4 (0,0,0,0) ra 0xffffffff804df90c sz 0
 0x98000000001bfdc0: mi_switch+0x1e4 (0,0,0,0) ra 0xffffffff804dcf44 sz 96
 0x98000000001bfe20: softint_dispatch+0xec (0,0,0,0) ra 0xffffffff80200234 =
 sz 128
 0x98000000001bfea0: softint_fast_dispatch+0x7c (0,0,0,0) ra 0 sz 32
 User-level: pid 0.6
 db> bt/a 980000004d534e00
 pid 11131.11131 at 0x980000000289c000
 0x980000000289f4c0: kernel_text+0xe4 (0,0,0,0) ra 0xffffffff8020025c sz 0
 0x980000000289f4c0: softint_fast_dispatch+0xa4 (0x980000004eed7280,0,0,0) =
 ra 0xffffffff8026f794 sz 32
 0x980000000289f4e0: softint_process+0xfc (0x980000004eed7280,0,0,0) ra 0xf=
 fffffff802578ec sz 64
 0x980000000289f520: mips64r2_kern_intr+0xec (0x8f00,0x4,0x10,0xffffffff807=
 a83c0) ra 0xffffffff80258894 sz 352
 0x980000000289f680: ras_mutex_spin_enter+0x18 (0x8f00,0x4,0x10,0xffffffff8=
 07a83c0) ra 0 sz 0
 User-level: pid 0.6
 
 so it seems that the makemandb process got interrupted by a fast
 softint for serial, and i guess that something in this called
 pmap_update(), which called pmap_md_tlb_check_entry() that asserts.
 
 
 i wonder if this is doing something to set dirty leading to this
 as a toctou bug?
 
 
 .mrg.