From bd85f4b37ddf2da22ccf5b29d264b2459b6722df Mon Sep 17 00:00:00 2001 From: Xie XiuQi Date: Tue, 27 Sep 2016 15:07:12 +0800 Subject: ipmi: fix crash on reading version from proc after unregisted bmc I meet a crash, which could be reproduce: 1) while true; do cat /proc/ipmi/0/version; done 2) modprobe -rv ipmi_si ipmi_msghandler ipmi_devintf [82761.021137] IPMI BT: req2rsp=5 secs retries=2 [82761.034524] ipmi device interface [82761.222218] ipmi_si ipmi_si.0: Found new BMC (man_id: 0x0007db, prod_id: 0x0001, dev_id: 0x01) [82761.222230] ipmi_si ipmi_si.0: IPMI bt interface initialized [82903.922740] BUG: unable to handle kernel NULL pointer dereference at 00000000000002d4 [82903.930952] IP: [] smi_version_proc_show+0x18/0x40 [ipmi_msghandler] [82903.939220] PGD 86693a067 PUD 865304067 PMD 0 [82903.943893] Thread overran stack, or stack corrupted [82903.949034] Oops: 0000 [#1] SMP [82903.983091] Modules linked in: ipmi_si(-) ipmi_msghandler binfmt_misc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ... [82904.057285] pps_core scsi_transport_sas dm_mod vfio_iommu_type1 vfio xt_sctp nf_conntrack_proto_sctp nf_nat_proto_sctp nf_nat nf_conntrack sctp libcrc32c [last unloaded: ipmi_devintf] [82904.073169] CPU: 37 PID: 28089 Comm: cat Tainted: GF O ---- ------- 3.10.0-327.28.3.el7.x86_64 #1 [82904.083373] Hardware name: Huawei RH2288H V3/BC11HGSA0, BIOS 3.22 05/16/2016 [82904.090592] task: ffff880101cc2e00 ti: ffff880369c54000 task.ti: ffff880369c54000 [82904.098414] RIP: 0010:[] [] smi_version_proc_show+0x18/0x40 [ipmi_msghandler] [82904.109124] RSP: 0018:ffff880369c57e70 EFLAGS: 00010203 [82904.114608] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000024688470 [82904.121912] RDX: fffffffffffffff4 RSI: ffffffffa0313404 RDI: ffff8808670ce200 [82904.129218] RBP: ffff880369c57e70 R08: 0000000000019720 R09: ffffffff81204a27 [82904.136521] R10: ffff88046f803300 R11: 0000000000000246 R12: ffff880662399700 [82904.143828] R13: 0000000000000001 R14: ffff880369c57f48 R15: ffff8808670ce200 [82904.151128] FS: 00007fb70c9ca740(0000) GS:ffff88086e340000(0000) knlGS:0000000000000000 [82904.159557] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [82904.165473] CR2: 00000000000002d4 CR3: 0000000864c0c000 CR4: 00000000003407e0 [82904.172778] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [82904.180084] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [82904.187385] Stack: [82904.189573] ffff880369c57ee0 ffffffff81204f1a 00000000122a2427 0000000001426000 [82904.197392] ffff8808670ce238 0000000000010000 0000000000000000 0000000000000fff [82904.205198] 00000000122a2427 ffff880862079600 0000000001426000 ffff880369c57f48 [82904.212962] Call Trace: [82904.219667] [] seq_read+0xfa/0x3a0 [82904.224893] [] proc_reg_read+0x3d/0x80 [82904.230468] [] vfs_read+0x9c/0x170 [82904.235689] [] SyS_read+0x7f/0xe0 [82904.240816] [] system_call_fastpath+0x16/0x1b [82904.246991] Code: 30 a0 e8 0c 6f ef e0 5b 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8b 47 78 55 48 c7 c6 04 34 31 a0 48 89 e5 48 8b 40 50 <0f> b6 90 d4 02 00 00 31 c0 89 d1 83 e2 0f c0 e9 04 0f b6 c9 e8 [82904.267710] RIP [] smi_version_proc_show+0x18/0x40 [ipmi_msghandler] [82904.276079] RSP [82904.279734] CR2: 00000000000002d4 [82904.283731] ---[ end trace a69e4328b49dd7c4 ]--- [82904.328118] Kernel panic - not syncing: Fatal exception Reading versin from /proc need bmc device struct available. So in this patch we move add/remove_proc_entries between ipmi_bmc_register and ipmi_bmc_unregister. Cc: Kefeng Wang Signed-off-by: Xie XiuQi Signed-off-by: Corey Minyard --- drivers/char/ipmi/ipmi_msghandler.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index d8619998cfb5..fcdd886819f5 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -2891,11 +2891,11 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, intf->curr_channel = IPMI_MAX_CHANNELS; } + rv = ipmi_bmc_register(intf, i); + if (rv == 0) rv = add_proc_entries(intf, i); - rv = ipmi_bmc_register(intf, i); - out: if (rv) { if (intf->proc_dir) @@ -2982,8 +2982,6 @@ int ipmi_unregister_smi(ipmi_smi_t intf) int intf_num = intf->intf_num; ipmi_user_t user; - ipmi_bmc_unregister(intf); - mutex_lock(&smi_watchers_mutex); mutex_lock(&ipmi_interfaces_mutex); intf->intf_num = -1; @@ -3007,6 +3005,7 @@ int ipmi_unregister_smi(ipmi_smi_t intf) mutex_unlock(&ipmi_interfaces_mutex); remove_proc_entries(intf); + ipmi_bmc_unregister(intf); /* * Call all the watcher interfaces to tell them that -- cgit v1.2.3