Re: [PATCH 0/2] sunrpc: Fix issues with cache_detail nextcheck updates

[cel]

From: Chuck Lever <chuck.lever@xxxxxxxxxx>

On Sat, 01 Mar 2025 14:48:34 +0800, Long Li wrote:
> During memory fault injection testing with nfsd restart, I encountered an
> issue where NFS client threads would hang for around 1800 seconds. Analysis
> showed that nfsd threads were blocked for approximately 1800 seconds with
> the following scenario:
> 
>   PID: 3941444  TASK: ffff0000cf170040  CPU: 0    COMMAND: "nfsd"
>    #0 [ffff80008d387120] __switch_to at ffffc4ef3c7a6af0
>    #1 [ffff80008d387170] __schedule at ffffc4ef3c7a73a4
>    #2 [ffff80008d3872c0] schedule at ffffc4ef3c7a8074
>    #3 [ffff80008d387300] schedule_timeout at ffffc4ef3c7b7b60
>    #4 [ffff80008d387470] wait_for_common at ffffc4ef3c7a944c
>    #5 [ffff80008d387560] wait_for_completion_interruptible_timeout at ffffc4ef3c7a9630
>    #6 [ffff80008d387570] cache_wait_req at ffffc4ef3c6804dc
>    #7 [ffff80008d3876f0] cache_check at ffffc4ef3c680740
>    #8 [ffff80008d3877d0] exp_find_key at ffffc4ef3b6e293c
>    #9 [ffff80008d387910] exp_find at ffffc4ef3b6e2ccc
>   #10 [ffff80008d387980] rqst_exp_find at ffffc4ef3b6e445c
>   #11 [ffff80008d3879e0] exp_pseudoroot at ffffc4ef3b6e4984
>   #12 [ffff80008d387a90] nfsd4_putrootfh at ffffc4ef3b6f8720
>   #13 [ffff80008d387ab0] nfsd4_proc_compound at ffffc4ef3b6fe4cc
>   #14 [ffff80008d387b70] nfsd_dispatch at ffffc4ef3b6cf428
>   #15 [ffff80008d387c30] svc_process_common at ffffc4ef3c66235c
>   #16 [ffff80008d387d20] svc_process at ffffc4ef3c6652f8
>   #17 [ffff80008d387d90] svc_recv at ffffc4ef3c68c5d0
>   #18 [ffff80008d387e10] nfsd at ffffc4ef3b6cb968
>   #19 [ffff80008d387e60] kthread at ffffc4ef3ad4aca4
> 
> [...]

Applied to nfsd-testing, thanks!

[1/2] sunrpc: update nextcheck time when adding new cache entries
      commit: c2689130933a68ee9d6bca39ca5c3c7741279ea3
[2/2] sunrpc: fix race in cache cleanup causing stale nextcheck time
      commit: 48a9b0e38470d7f16625dbf51f85d0fb7315b15b

--
Chuck Lever