From c608966f3f9c2dca596967501d00753282b395fc Mon Sep 17 00:00:00 2001 From: Zhang Yuchen Date: Sun, 9 Oct 2022 17:18:09 +0800 Subject: [PATCH] ipmi: fix msg stack when IPMI is disconnected If you continue to access and send messages at a high frequency (once every 55s) when the IPMI is disconnected, messages will accumulate in intf->[hp_]xmit_msg. If it lasts long enough, it takes up a lot of memory. The reason is that if IPMI is disconnected, each message will be set to IDLE after it returns to HOSED through IDLE->ERROR0->HOSED. The next message goes through the same process when it comes in. This process needs to wait for IBF_TIMEOUT * (MAX_ERROR_RETRIES + 1) = 55s. Each message takes 55S to destroy. This results in a continuous increase in memory. I find that if I wait 5 seconds after the first message fails, the status changes to ERROR0 in smi_timeout(). The next message will return the error code IPMI_NOT_IN_MY_STATE_ERR directly without wait. This is more in line with our needs. So instead of setting each message state to IDLE after it reaches the state HOSED, set state to ERROR0. After testing, the problem has been solved, no matter how many consecutive sends, will not cause continuous memory growth. It also returns to normal immediately after the IPMI is restored. In addition, the HOSED state should also count as invalid. So the HOSED is removed from the invalid judgment in start_kcs_transaction(). The verification operations are as follows: 1. Use BPF to record the ipmi_alloc/free_smi_msg(). $ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc %p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}' 2. Exec `date; time for x in $(seq 1 2); do ipmitool mc info; done`. 3. Record the output of `time` and when free all msgs. Before: `time` takes 120s, This is because `ipmitool mc info` send 4 msgs and waits only 15 seconds for each message. Last msg is free after 440s. $ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc %p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}' Oct 05 11:40:55 Attaching 2 probes... Oct 05 11:41:12 alloc 0xffff9558a05f0c00 Oct 05 11:41:27 alloc 0xffff9558a05f1a00 Oct 05 11:41:42 alloc 0xffff9558a05f0000 Oct 05 11:41:57 alloc 0xffff9558a05f1400 Oct 05 11:42:07 free 0xffff9558a05f0c00 Oct 05 11:42:07 alloc 0xffff9558a05f7000 Oct 05 11:42:22 alloc 0xffff9558a05f2a00 Oct 05 11:42:37 alloc 0xffff9558a05f5a00 Oct 05 11:42:52 alloc 0xffff9558a05f3a00 Oct 05 11:43:02 free 0xffff9558a05f1a00 Oct 05 11:43:57 free 0xffff9558a05f0000 Oct 05 11:44:52 free 0xffff9558a05f1400 Oct 05 11:45:47 free 0xffff9558a05f7000 Oct 05 11:46:42 free 0xffff9558a05f2a00 Oct 05 11:47:37 free 0xffff9558a05f5a00 Oct 05 11:48:32 free 0xffff9558a05f3a00 $ root@dc00-pb003-t106-n078:~# date;time for x in $(seq 1 2); do ipmitool mc info; done Wed Oct 5 11:41:12 CST 2022 No data available Get Device ID command failed No data available No data available No valid response received Get Device ID command failed: Unspecified error No data available Get Device ID command failed No data available No data available No valid response received No data available Get Device ID command failed real 1m55.052s user 0m0.001s sys 0m0.001s After: `time` takes 55s, all msgs is returned and free after 55s. $ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc %p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}' Oct 07 16:30:35 Attaching 2 probes... Oct 07 16:30:45 alloc 0xffff955943aa9800 Oct 07 16:31:00 alloc 0xffff955943aacc00 Oct 07 16:31:15 alloc 0xffff955943aa8c00 Oct 07 16:31:30 alloc 0xffff955943aaf600 Oct 07 16:31:40 free 0xffff955943aa9800 Oct 07 16:31:40 free 0xffff955943aacc00 Oct 07 16:31:40 free 0xffff955943aa8c00 Oct 07 16:31:40 free 0xffff955943aaf600 Oct 07 16:31:40 alloc 0xffff9558ec8f7e00 Oct 07 16:31:40 free 0xffff9558ec8f7e00 Oct 07 16:31:40 alloc 0xffff9558ec8f7800 Oct 07 16:31:40 free 0xffff9558ec8f7800 Oct 07 16:31:40 alloc 0xffff9558ec8f7e00 Oct 07 16:31:40 free 0xffff9558ec8f7e00 Oct 07 16:31:40 alloc 0xffff9558ec8f7800 Oct 07 16:31:40 free 0xffff9558ec8f7800 root@dc00-pb003-t106-n078:~# date;time for x in $(seq 1 2); do ipmitool mc info; done Fri Oct 7 16:30:45 CST 2022 No data available Get Device ID command failed No data available No data available No valid response received Get Device ID command failed: Unspecified error Get Device ID command failed: 0xd5 Command not supported in present state Get Device ID command failed: Command not supported in present state real 0m55.038s user 0m0.001s sys 0m0.001s Signed-off-by: Zhang Yuchen Message-Id: <20221009091811.40240-2-zhangyuchen.lcr@bytedance.com> Signed-off-by: Corey Minyard --- drivers/char/ipmi/ipmi_kcs_sm.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/char/ipmi/ipmi_kcs_sm.c b/drivers/char/ipmi/ipmi_kcs_sm.c index efda90dcf5b3..ecfcb50302f6 100644 --- a/drivers/char/ipmi/ipmi_kcs_sm.c +++ b/drivers/char/ipmi/ipmi_kcs_sm.c @@ -122,10 +122,10 @@ struct si_sm_data { unsigned long error0_timeout; }; -static unsigned int init_kcs_data(struct si_sm_data *kcs, - struct si_sm_io *io) +static unsigned int init_kcs_data_with_state(struct si_sm_data *kcs, + struct si_sm_io *io, enum kcs_states state) { - kcs->state = KCS_IDLE; + kcs->state = state; kcs->io = io; kcs->write_pos = 0; kcs->write_count = 0; @@ -140,6 +140,12 @@ static unsigned int init_kcs_data(struct si_sm_data *kcs, return 2; } +static unsigned int init_kcs_data(struct si_sm_data *kcs, + struct si_sm_io *io) +{ + return init_kcs_data_with_state(kcs, io, KCS_IDLE); +} + static inline unsigned char read_status(struct si_sm_data *kcs) { return kcs->io->inputb(kcs->io, 1); @@ -270,7 +276,7 @@ static int start_kcs_transaction(struct si_sm_data *kcs, unsigned char *data, if (size > MAX_KCS_WRITE_SIZE) return IPMI_REQ_LEN_EXCEEDED_ERR; - if ((kcs->state != KCS_IDLE) && (kcs->state != KCS_HOSED)) { + if (kcs->state != KCS_IDLE) { dev_warn(kcs->io->dev, "KCS in invalid state %d\n", kcs->state); return IPMI_NOT_IN_MY_STATE_ERR; } @@ -495,7 +501,7 @@ static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time) } if (kcs->state == KCS_HOSED) { - init_kcs_data(kcs, kcs->io); + init_kcs_data_with_state(kcs, kcs->io, KCS_ERROR0); return SI_SM_HOSED; }