From a73914c35b05d80f8ce78288e10056c91090b666 Mon Sep 17 00:00:00 2001 From: Mark Salyzyn Date: Thu, 22 Sep 2011 08:32:23 -0700 Subject: [PATCH] [SCSI] libsas: fix panic when single phy is disabled on a wide port When a wide port is being utilized to a target, if one disables only one of the phys, we get an OS crash: BUG: unable to handle kernel NULL pointer dereference at 0000000000000238 IP: [] mutex_lock+0x21/0x50 PGD 4103f5067 PUD 41dba9067 PMD 0 Oops: 0002 [#1] SMP last sysfs file: /sys/bus/pci/slots/5/address CPU 0 Modules linked in: pm8001(U) ses enclosure fuse nfsd exportfs autofs4 ipmi_devintf ipmi_si ipmi_msghandler nfs lockd fscache nfs_acl auth_rpcgss 8021q fcoe libfcoe garp libfc scsi_transport_fc stp scsi_tgt llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table ipv6 sr_mod cdrom dm_mirror dm_region_hash dm_log uinput sg i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support e1000e mlx4_ib ib_mad ib_core mlx4_en mlx4_core ext3 jbd mbcache sd_mod crc_t10dif usb_storage ata_generic pata_acpi ata_piix libsas(U) scsi_transport_sas dm_mod [last unloaded: pm8001] Modules linked in: pm8001(U) ses enclosure fuse nfsd exportfs autofs4 ipmi_devintf ipmi_si ipmi_msghandler nfs lockd fscache nfs_acl auth_rpcgss 8021q fcoe libfcoe garp libfc scsi_transport_fc stp scsi_tgt llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table ipv6 sr_mod cdrom dm_mirror dm_region_hash dm_log uinput sg i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support e1000e mlx4_ib ib_mad ib_core mlx4_en mlx4_core ext3 jbd mbcache sd_mod crc_t10dif usb_storage ata_generic pata_acpi ata_piix libsas(U) scsi_transport_sas dm_mod [last unloaded: pm8001] Pid: 5146, comm: scsi_wq_5 Not tainted 2.6.32-71.29.1.el6.lustre.7.x86_64 #1 Storage Server RIP: 0010:[] [] mutex_lock+0x21/0x50 RSP: 0018:ffff8803e4e33d30 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000238 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8803e664c800 RDI: 0000000000000238 RBP: ffff8803e4e33d40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000238 R14: ffff88041acb7200 R15: ffff88041c51ada0 FS: 0000000000000000(0000) GS:ffff880028200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000238 CR3: 0000000410143000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process scsi_wq_5 (pid: 5146, threadinfo ffff8803e4e32000, task ffff8803e4e294a0) Stack: ffff8803e664c800 0000000000000000 ffff8803e4e33d70 ffffffffa001f06e <0> ffff8803e4e33d60 ffff88041c51ada0 ffff88041acb7200 ffff88041bc0aa00 <0> ffff8803e4e33d90 ffffffffa0032b6c 0000000000000014 ffff88041acb7200 Call Trace: [] sas_port_delete_phy+0x2e/0xa0 [scsi_transport_sas] [] sas_unregister_devs_sas_addr+0xac/0xe0 [libsas] [] sas_ex_revalidate_domain+0x204/0x330 [libsas] [] ? sas_revalidate_domain+0x0/0x90 [libsas] [] sas_revalidate_domain+0x65/0x90 [libsas] [] worker_thread+0x170/0x2a0 [] ? autoremove_wake_function+0x0/0x40 [] ? worker_thread+0x0/0x2a0 [] kthread+0x96/0xa0 [] child_rip+0xa/0x20 [] ? kthread+0x0/0xa0 [] ? child_rip+0x0/0x20 Code: ff ff 85 c0 75 ed eb d6 66 90 55 48 89 e5 48 83 ec 10 48 89 1c 24 4c 89 64 24 08 0f 1f 44 00 00 48 89 fb e8 92 f4 ff ff 48 89 df ff 0f 79 05 e8 25 00 00 00 65 48 8b 04 25 08 cc 00 00 48 2d RIP [] mutex_lock+0x21/0x50 RSP CR2: 0000000000000238 The following patch is admittedly a band-aid, and does not solve the root cause, but it still is a good candidate for hardening as a pointer check before reference. Signed-off-by: Mark Salyzyn Tested-by: Jack Wang Cc: stable@kernel.org Signed-off-by: James Bottomley --- drivers/scsi/libsas/sas_expander.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index c9e3dc024bc3..16ad97df5ba6 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -1769,10 +1769,12 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent, sas_disable_routing(parent, phy->attached_sas_addr); } memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE); - sas_port_delete_phy(phy->port, phy->phy); - if (phy->port->num_phys == 0) - sas_port_delete(phy->port); - phy->port = NULL; + if (phy->port) { + sas_port_delete_phy(phy->port, phy->phy); + if (phy->port->num_phys == 0) + sas_port_delete(phy->port); + phy->port = NULL; + } } static int sas_discover_bfs_by_root_level(struct domain_device *root, -- 2.34.1