Re: kernel BUG at net/sunrpc/svc.c:570 after updating from v5.15.153 to v5.15.155

[Chris Packham]

On 24/04/24 12:54, Chris Packham wrote:
> Hi Jeff, Chuck, Greg,
>
> After updating one of our builds along the 5.15.y LTS branch our 
> testing caught a new kernel bug. Output below.
>
> I haven't dug into it yet but wondered if it rang any bells.

A bit more info. This is happening at "reboot" for us. Our embedded 
devices use a bit of a hacked up reboot process so that they come back 
faster in the case of a failure.

It doesn't happen with a proper `systemctl reboot` or with a SYSRQ+B

I can trigger it with `killall -9 nfsd` which I'm not sure is a 
completely legit thing to do to kernel threads but it's probably close 
to what our customized reboot does.

>
> Thanks,
> Chris
>
> [   91.605109] ------------[ cut here ]------------
> [   91.605122] kernel BUG at net/sunrpc/svc.c:570!
> [   91.605129] Internal error: Oops - BUG: 00000000f2000800 [#1] 
> PREEMPT SMP
> [   91.610643] Modules linked in: mvcpss(O) platform_driver(O) 
> ipifwd(O) xt_l2tp xt_hashlimit xt_conntrack xt_addrtype xt_LOG 
> xt_CHECKSUM wp512 vxlan veth twofish_generic twofish_common sr9800 
> smsc95xx smsc75xx smsc sm3_generic sha512_arm64 sha3_generic 
> serpent_generic rtl8150 rpcsec_gss_krb5 rmd160 poly1305_generic plusb 
> pegasus optee_rng nbd microchip md4 md_mod mcs7830 lrw libpoly1305 
> lan78xx l2tp_ip6 l2tp_ip l2tp_eth l2tp_netlink l2tp_core udp_tunnel 
> ipt_REJECT nf_reject_ipv4 ip6table_nat ip6table_mangle ip6table_filter 
> ip6t_ipv6header ip6t_REJECT ip6_udp_tunnel ip6_tables dm9601 dm_zero 
> dm_mirror dm_region_hash dm_log dm_mod diag tipc cuse cts 
> cpufreq_powersave cpufreq_conservative chacha_generic chacha20poly1305 
> chacha_neon libchacha cast6_generic cast5_generic cast_common 
> camellia_generic blowfish_generic blowfish_common auth_rpcgss 
> oid_registry at25 arm_smccc_trng aes_neon_blk idprom_mtd(O) 
> idprom_i2c(O) epi3_boardinfo_i2c(O) x250(O) psuslot_epi3_register(O) 
> psuslot_gpio_group(O)
> [   91.610809]  psuslot(O)
> [   91.611822] watchdog: watchdog1: watchdog did not stop!
> [   91.697065]  gpiopins_boardinfo(O) idprom(O) epi3_boardinfo(O) 
> boardinfo(O) i2c_gpio i2c_algo_bit i2c_mv64xxx pluggable(O) 
> led_enable(O) omap_rng rng_core atl_reset(O) sbsa_gwdt uio_pdrv_genirq
> [   91.697096] CPU: 2 PID: 1770 Comm: nfsd Kdump: loaded Tainted: 
> G           O      5.15.155 #1
> [   91.697103] Hardware name: Allied Telesis x250-28XTm (DT)
> [   91.697107] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS 
> BTYPE=--)
> [   91.697112] pc : svc_destroy+0x84/0xac
> [   91.701202] watchdog: watchdog0: watchdog did not stop!
> [   91.702215] lr : svc_destroy+0x2c/0xac
> [   91.702220] sp : ffff80000bb3bde0
> [   91.702223] x29: ffff80000bb3bde0 x28: 0000000000000000 x27: 
> 0000000000000000
> [   91.746095] x26: 0000000000000000 x25: ffff00000dbfaa40 x24: 
> ffff000016c14000
> [   91.746101] x23: ffff800008395c00 x22: ffff00000ee9f284 x21: 
> ffff00000eea9e10
> [   91.746108] x20: ffff00000eea9e00 x19: ffff00000eea9e14 x18: 
> ffff800008e99000
> [   91.769526] x17: 0000000000000006 x16: 0000000000000000 x15: 
> 0000000000000001
> [   91.776782] x14: 00000000fffffffd x13: fffffc0000000000 x12: 
> ffff800076bc2000
> [   91.784031] x11: ffff00007fba5c10 x10: ffff800076bc2000 x9 : 
> ffff8000092207c0
> [   91.784038] x8 : fffffc000055eb08 x7 : ffff00000ef6c4c0 x6 : 
> fffffc0001f872c8
> [   91.795823] x5 : 0000000000000100 x4 : ffff00007fbaeda8 x3 : 
> 0000000000000000
> [   91.801684] x2 : 0000000000000000 x1 : ffff00000d8f8018 x0 : 
> ffff00000eea9e30
> [   91.807545] Call trace:
> [   91.810088]  svc_destroy+0x84/0xac
> [   91.813586]  svc_exit_thread+0x108/0x15c
> [   91.816998]  nfsd+0x178/0x1a0
> [   91.818673]  kthread+0x150/0x160
> [   91.820610]  ret_from_fork+0x10/0x20
> [   91.820620] Code: a94153f3 a8c27bfd d50323bf d65f03c0 (d4210000)
> [   91.820629] SMP: stopping secondary CPUs
> [   91.830433] Starting crashdump kernel...
> [   91.833064] Bye!