On Thu, Jan 18 2018, Anna Schumaker wrote: > On 01/18/2018 01:39 PM, Anna Schumaker wrote: >> Hi Neil, >> >> On 01/08/2018 12:26 AM, NeilBrown wrote: >>> The SUNRPC credential framework was put together before >>> Linux has 'struct cred'. Now that we have it, it makes sense to >>> use it. >>> This first step just includes a suitable 'struct cred *' pointer >>> in every 'struct auth_cred' and almost every 'struct rpc_cred'. >>> >>> The rpc_cred used for auth_null has a NULL 'struct cred *' as nothing >>> else really makes sense. >>> >>> For rpc_cred, the pointer is reference counted. >>> For auth_cred it isn't. struct auth_cred are either allocated on >>> the stack, in which case the thread owns a reference to the auth, >>> or are part of 'struct generic_cred' in which case gc_base owns the >>> reference and acred shares it. > > This patch is also causing a kernel panic for me if I mount using sec=krb5, run cthon tests, and then unmount. Here is the log message I'm getting: > > [ 82.599174] Kernel panic - not syncing: CRED: put_cred_rcu() sees 00000000f5847a57 with usage -1 > [ 82.599174] > [ 82.600227] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc7-ANNA+ #14336 > [ 82.600801] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 82.601435] Call Trace: > [ 82.601639] <IRQ> > [ 82.601830] dump_stack+0x5c/0x7e > [ 82.602125] panic+0xdf/0x228 > [ 82.602383] ? try_to_wake_up+0x24b/0x420 > [ 82.602853] put_cred_rcu+0x8a/0x90 > [ 82.603183] rcu_process_callbacks+0x1ab/0x4f0 > [ 82.603577] __do_softirq+0xcc/0x305 > [ 82.603881] irq_exit+0xa9/0xb0 > [ 82.604159] smp_apic_timer_interrupt+0x5b/0x140 > [ 82.604528] apic_timer_interrupt+0x98/0xa0 > [ 82.604892] </IRQ> > [ 82.605133] RIP: 0010:native_safe_halt+0x2/0x10 > [ 82.605678] RSP: 0018:ffffffff82003ea8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff11 > [ 82.606619] RAX: 0000000080000000 RBX: 0000000000000000 RCX: 0000000000000000 > [ 82.607270] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > [ 82.608077] RBP: 0000000000000000 R08: 0000000000000002 R09: 000000000001ea40 > [ 82.609066] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 > [ 82.609951] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > [ 82.610771] default_idle+0x15/0x120 > [ 82.611128] do_idle+0x15c/0x1c0 > [ 82.611371] cpu_startup_entry+0x6a/0x70 > [ 82.611762] start_kernel+0x445/0x465 > [ 82.612104] secondary_startup_64+0xa5/0xb0 > [ 82.612561] Kernel Offset: disabled > [ 82.612862] ---[ end Kernel panic - not syncing: CRED: put_cred_rcu() sees 00000000f5847a57 with usage -1 > [ 82.612862] > That's not good. I've just read through the patches again and didn't find anything that could cause this, so I must have missed something. You say "This patch is also causing", but I assume it is the whole patch set rather than just this one patch - is that correct? Also, have you run tests without sec=krb5 and not had the error? I'll try to set up some more thorough testing myself. Thanks, NeilBrown
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