Subject: raidstrategy() isn't interrupt-safe
To: None <>
From: Manuel Bouyer <>
List: tech-kern
Date: 05/14/2005 15:14:56
a recent report on the port-xen list shows this stack trace:
panic: pool_get: rf_rad_pl: must have NOWAIT
Stopped at      netbsd:cpu_Debugger+0x4        leave
cpu_Debugger(2ff,c9f31,2fe,401,c0657c4c) at netbsd:cpu_Debugger+0x4
panic(c05bb5c0,c0569d73,c0720d50,c04cc336,c09a6700) at netbsd:panic+0x121
pool_get(c0657c4c,2,c0e26000,10000,0) at netbsd:pool_get+0xf9
rf_AllocRaidAccDesc(c0aa2000,72,401,0,1) at netbsd:rf_AllocRaidAccDesc+0x30
rf_DoAccess(c0aa200,72,1,401,0) at netbsd:rf_DoAccess+0x40
raidstart(c0aa2000,c0b07000,0,0,1) at netbsd:raidstart+0x28f
raidstrategy(c0b07000,1,c0a4c118,c0acc800,c09d1084) at
ccdstart(c0a6d000,c09cd000,0,c0a4c118,c0a4c118) at netbsd:ccdstart+0x137
ccdstrategy(c09cd000,1,1,c09cd07c,0) at netbsd:ccdstrategy+0x142
xbdback_do_io(c09cd000,c09cd000,c0720dc0,c0212b42,c0a4c118) at

raidstrategy() ends up being called from interrupt context here,
and ends up calling pool_get(PR_WAITOK).
Quoting a previous post from Jason Thorpe on tech-kern:
> There are lots of other things that might cause a disk's strategy  
> routine to be called from interrupt context (ccd / raidframe are good  
> examples).  Really, we need to audit ALL of the disk strategy  
> routines and ensure that they are IPL_BIO interrupt-context safe.

so raidframe is broken in this respect. Should I fill a PR about this ?

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference