[PATCH] scsi: libiscsi: use kvzalloc for iscsi_pool_init

[PATCH] scsi: libiscsi: use kvzalloc for iscsi_pool_init

[Kyle Fortin]

iscsiadm session login can fail with the following error:

iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com...
iscsiadm: initiator reported error (9 - internal error)

When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results
in 64K-sized kmallocs per session.  A system under fragmented slab
pressure may not have any 64K objects available and fail iscsiadm session
login. Even though memory objects of a smaller size are available, the
large order allocation ends up failing.

The kernel prints a warning and does dump_stack, like below:

iscsid: page allocation failure: order:4, mode:0xc0d0
CPU: 0 PID: 2456 Comm: iscsid Not tainted 4.1.12-61.1.28.el6uek.x86_64 #2
Call Trace:
 [<ffffffff816c6e40>] dump_stack+0x63/0x83
 [<ffffffff8118e58a>] warn_alloc_failed+0xea/0x140
 [<ffffffff81191df9>] __alloc_pages_slowpath+0x409/0x760
 [<ffffffff81192401>] __alloc_pages_nodemask+0x2b1/0x2d0
 [<ffffffffa048f6c0>] ? dev_attr_host_ipaddress+0x20/0xffffffffffffc722
 [<ffffffff811dc38f>] alloc_pages_current+0xaf/0x170
 [<ffffffff81192581>] alloc_kmem_pages+0x31/0xd0
 [<ffffffffa048f600>] ? iscsi_transport_group+0x20/0xffffffffffffc7e2
 [<ffffffff811ad738>] kmalloc_order+0x18/0x50
 [<ffffffff811ad7a4>] kmalloc_order_trace+0x34/0xe0
 [<ffffffff8146ee30>] ? transport_remove_classdev+0x70/0x70
 [<ffffffff811e843d>] __kmalloc+0x27d/0x2a0
 [<ffffffff810c8cbd>] ? complete_all+0x4d/0x60
 [<ffffffffa04af299>] iscsi_pool_init+0x69/0x160 [libiscsi]
 [<ffffffff81465d90>] ? device_initialize+0xb0/0xd0
 [<ffffffffa04af510>] iscsi_session_setup+0x180/0x2f4 [libiscsi]
 [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
 [<ffffffffa04c531f>] iscsi_sw_tcp_session_create+0xcf/0x150 [iscsi_tcp]
 [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
 [<ffffffffa048a633>] iscsi_if_create_session+0x33/0xd0
 [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
 [<ffffffffa048abd8>] iscsi_if_recv_msg+0x508/0x8c0 [scsi_transport_iscsi]
 [<ffffffff811922eb>] ? __alloc_pages_nodemask+0x19b/0x2d0
 [<ffffffff811e6d69>] ? __kmalloc_node_track_caller+0x209/0x2c0
 [<ffffffffa048b00c>] iscsi_if_rx+0x7c/0x200 [scsi_transport_iscsi]
 [<ffffffff81623dc6>] netlink_unicast+0x126/0x1c0
 [<ffffffff8162468c>] netlink_sendmsg+0x36c/0x400
 [<ffffffff815d2fed>] sock_sendmsg+0x4d/0x60
 [<ffffffff815d596a>] ___sys_sendmsg+0x30a/0x330
 [<ffffffff811bc72c>] ? handle_pte_fault+0x20c/0x230
 [<ffffffff811bc90c>] ? __handle_mm_fault+0x1bc/0x330
 [<ffffffff811bcb32>] ? handle_mm_fault+0xb2/0x1a0
 [<ffffffff815d5b99>] __sys_sendmsg+0x49/0x90
 [<ffffffff815d5bf9>] SyS_sendmsg+0x19/0x20
 [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71

Use kvzalloc for iscsi_pool in iscsi_pool_init.

Signed-off-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Tested-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Reviewed-by: Joseph Slember <joe.slember-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Reviewed-by: Lance Hartmann <lance.hartmann-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
 drivers/scsi/libiscsi.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index dd6828f..42381ad 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -2556,7 +2556,7 @@ int iscsi_eh_recover_target(struct scsi_cmnd *sc)
 	 * the array. */
 	if (items)
 		num_arrays++;
-	q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
+	q->pool = kvzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
 	if (q->pool == NULL)
 		return -ENOMEM;
 
@@ -2590,7 +2590,7 @@ void iscsi_pool_free(struct iscsi_pool *q)
 
 	for (i = 0; i < q->max; i++)
 		kfree(q->pool[i]);
-	kfree(q->pool);
+	kvfree(q->pool);
 }
 EXPORT_SYMBOL_GPL(iscsi_pool_free);
 
-- 
1.7.1

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Re: [PATCH] scsi: libiscsi: use kvzalloc for iscsi_pool_init

[The Lee-Man]

[-- Attachment #1.1: Type: text/plain, Size: 4791 bytes --]

On Wednesday, May 17, 2017 at 2:38:56 PM UTC-7, Kyle Fortin wrote:
>
> iscsiadm session login can fail with the following error: 
>
> iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com... 
> iscsiadm: initiator reported error (9 - internal error) 
>
> When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results 
> in 64K-sized kmallocs per session.  A system under fragmented slab 
> pressure may not have any 64K objects available and fail iscsiadm session 
> login. Even though memory objects of a smaller size are available, the 
> large order allocation ends up failing. 
>
> The kernel prints a warning and does dump_stack, like below: 
>
> iscsid: page allocation failure: order:4, mode:0xc0d0 
> CPU: 0 PID: 2456 Comm: iscsid Not tainted 4.1.12-61.1.28.el6uek.x86_64 #2 
> Call Trace: 
>  [<ffffffff816c6e40>] dump_stack+0x63/0x83 
>  [<ffffffff8118e58a>] warn_alloc_failed+0xea/0x140 
>  [<ffffffff81191df9>] __alloc_pages_slowpath+0x409/0x760 
>  [<ffffffff81192401>] __alloc_pages_nodemask+0x2b1/0x2d0 
>  [<ffffffffa048f6c0>] ? dev_attr_host_ipaddress+0x20/0xffffffffffffc722 
>  [<ffffffff811dc38f>] alloc_pages_current+0xaf/0x170 
>  [<ffffffff81192581>] alloc_kmem_pages+0x31/0xd0 
>  [<ffffffffa048f600>] ? iscsi_transport_group+0x20/0xffffffffffffc7e2 
>  [<ffffffff811ad738>] kmalloc_order+0x18/0x50 
>  [<ffffffff811ad7a4>] kmalloc_order_trace+0x34/0xe0 
>  [<ffffffff8146ee30>] ? transport_remove_classdev+0x70/0x70 
>  [<ffffffff811e843d>] __kmalloc+0x27d/0x2a0 
>  [<ffffffff810c8cbd>] ? complete_all+0x4d/0x60 
>  [<ffffffffa04af299>] iscsi_pool_init+0x69/0x160 [libiscsi] 
>  [<ffffffff81465d90>] ? device_initialize+0xb0/0xd0 
>  [<ffffffffa04af510>] iscsi_session_setup+0x180/0x2f4 [libiscsi] 
>  [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] 
>  [<ffffffffa04c531f>] iscsi_sw_tcp_session_create+0xcf/0x150 [iscsi_tcp] 
>  [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] 
>  [<ffffffffa048a633>] iscsi_if_create_session+0x33/0xd0 
>  [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] 
>  [<ffffffffa048abd8>] iscsi_if_recv_msg+0x508/0x8c0 [scsi_transport_iscsi] 
>  [<ffffffff811922eb>] ? __alloc_pages_nodemask+0x19b/0x2d0 
>  [<ffffffff811e6d69>] ? __kmalloc_node_track_caller+0x209/0x2c0 
>  [<ffffffffa048b00c>] iscsi_if_rx+0x7c/0x200 [scsi_transport_iscsi] 
>  [<ffffffff81623dc6>] netlink_unicast+0x126/0x1c0 
>  [<ffffffff8162468c>] netlink_sendmsg+0x36c/0x400 
>  [<ffffffff815d2fed>] sock_sendmsg+0x4d/0x60 
>  [<ffffffff815d596a>] ___sys_sendmsg+0x30a/0x330 
>  [<ffffffff811bc72c>] ? handle_pte_fault+0x20c/0x230 
>  [<ffffffff811bc90c>] ? __handle_mm_fault+0x1bc/0x330 
>  [<ffffffff811bcb32>] ? handle_mm_fault+0xb2/0x1a0 
>  [<ffffffff815d5b99>] __sys_sendmsg+0x49/0x90 
>  [<ffffffff815d5bf9>] SyS_sendmsg+0x19/0x20 
>  [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71 
>
> Use kvzalloc for iscsi_pool in iscsi_pool_init. 
>
> Signed-off-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 
> Tested-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 
> Reviewed-by: Joseph Slember <joe.slember-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 
> Reviewed-by: Lance Hartmann <lance.hartmann-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 
> --- 
>  drivers/scsi/libiscsi.c |    4 ++-- 
>  1 files changed, 2 insertions(+), 2 deletions(-) 
>
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c 
> index dd6828f..42381ad 100644 
> --- a/drivers/scsi/libiscsi.c 
> +++ b/drivers/scsi/libiscsi.c 
> @@ -2556,7 +2556,7 @@ int iscsi_eh_recover_target(struct scsi_cmnd *sc) 
>           * the array. */ 
>          if (items) 
>                  num_arrays++; 
> -        q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL); 
> +        q->pool = kvzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL); 
>          if (q->pool == NULL) 
>                  return -ENOMEM; 
>   
> @@ -2590,7 +2590,7 @@ void iscsi_pool_free(struct iscsi_pool *q) 
>   
>          for (i = 0; i < q->max; i++) 
>                  kfree(q->pool[i]); 
> -        kfree(q->pool); 
> +        kvfree(q->pool); 
>  } 
>  EXPORT_SYMBOL_GPL(iscsi_pool_free); 
>   
> -- 
> 1.7.1


Signed-off-by: Lee Duncan <lduncan-IBi9RG/b67k@public.gmane.org> 

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[-- Attachment #1.2: Type: text/html, Size: 7106 bytes --]

Re: [PATCH] scsi: libiscsi: use kvzalloc for iscsi_pool_init

[Martin K. Petersen]

Kyle,

> Use kvzalloc for iscsi_pool in iscsi_pool_init.

Applied to 4.13/scsi-queue. Thank you!

-- 
Martin K. Petersen	Oracle Linux Engineering

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