Hi Corey,


On 08/24/2018 06:38 PM, Corey Minyard wrote:

On 08/24/2018 06:10 AM, George Cherian wrote:
Dont set ssif_info->intf to NULL before ipmi_unresgiter_smi.
shutdown_ssif will anyways free ssif_info.

This is correct, but it goes a little deeper.  I just sent out a
patch yesterday that included this.

Yes I saw the patch now, https://sourceforge.net/p/openipmi/mailman/message/36397896/
I will test and update in that thread.


Thanks,

-corey

Following crash is obsearved if ssif_info->intf is set to NULL
before ipmi_unregister_smi.

  CPU: 119 PID: 7317 Comm: kssif000e Not tainted 4.18.0+ #80
  Hardware name: Cavium Inc. Saber/Saber, BIOS Cavium reference firmware version 7.0 08/04/2018
  pstate: 20400009 (nzCv daif +PAN -UAO)
  pc : ipmi_smi_msg_received+0x44/0x3bc [ipmi_msghandler]
  lr : deliver_recv_msg+0x30/0x5c [ipmi_ssif]
  sp : ffff000037a0fd20
  x29: ffff000037a0fd20 x28: 0000000000000000
  x27: ffff0000047e08f0 x26: ffff800ed9375800
  x25: ffff000037a0fe00 x24: ffff000009073000
  x23: 0000000000000013 x22: 0000000000000000
  x21: 0000000000007000 x20: ffff800adce18400
  x19: 0000000000000000 x18: ffff00003742fd38
  x17: ffff0000089960f0 x16: 000000000000000e
  x15: 0000000000000007 x14: 0000000000000000
  x13: 0000000000000000 x12: 0000000000000033
  x11: 0000000000000381 x10: 0000000000000ba0
  x9 : 0000000000000000 x8 : ffff800ac001fc00
  x7 : ffff7fe003b4d800 x6 : ffff800adce1854b
  x5 : 0000000000000014 x4 : 0000000000000004
  x3 : 0000000000000000 x2 : 0000000000000002
  x1 : 567cb12f8b916b00 x0 : 0000000000000002
  Process kssif000e (pid: 7317, stack limit = 0x0000000041077d8a)
  Call trace:
   ipmi_smi_msg_received+0x44/0x3bc [ipmi_msghandler]
   deliver_recv_msg+0x30/0x5c [ipmi_ssif]
   msg_done_handler+0x2f0/0x66c [ipmi_ssif]
   ipmi_ssif_thread+0x108/0x124 [ipmi_ssif]
   kthread+0x108/0x134
   ret_from_fork+0x10/0x18
  Code: b9402280 91401e75 f90037a1 7100041f (b945bab6)
  ---[ end trace fb7d748bc7b17490 ]---
  Kernel panic - not syncing: Fatal exception
  SMP: stopping secondary CPUs
  Kernel Offset: disabled
  CPU features: 0x23800c38
  Memory Limit: none
  ---[ end Kernel panic - not syncing: Fatal exception ]---

Signed-off-by: George Cherian <george.cher...@cavium.com>
---
  drivers/char/ipmi/ipmi_ssif.c | 5 +----
  1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index ccdf6b1..1490636 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1226,7 +1226,6 @@ static void shutdown_ssif(void *send_info)
  static int ssif_remove(struct i2c_client *client)
  {
      struct ssif_info *ssif_info = i2c_get_clientdata(client);
-     struct ipmi_smi *intf;
      struct ssif_addr_info *addr_info;

      if (!ssif_info)
@@ -1236,9 +1235,7 @@ static int ssif_remove(struct i2c_client *client)
       * After this point, we won't deliver anything asychronously
       * to the message handler.  We can unregister ourself.
       */
-     intf = ssif_info->intf;
-     ssif_info->intf = NULL;
-     ipmi_unregister_smi(intf);
+     ipmi_unregister_smi(ssif_info->intf);

      list_for_each_entry(addr_info, &ssif_infos, link) {
              if (addr_info->client == client) {


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