from:"Liu Xiang"

[PATCH v2] usb: musb: host: Fix NULL pointer dereference in SMP environment

2016-02-27 Thread Liu Xiang

In multi-core SoC, if enable USB endpoint/transmit urb/disable
USB endpoint repeatedly,it can cause a NULL pointer dereference bug:

Unable to handle kernel NULL pointer dereference at virtual address 0010
pgd = d3eb4000
[0010] *pgd=
Internal error: Oops: 5 [#1] PREEMPT SMP
Pid: 1017, comm:  mediaserver
CPU: 0Not tainted  (3.0.101-ZXICTOS_V2.00.20_P2B4_ZTE_ZX296700_ASIC+ #2)
PC is at musb_h_disable+0xfc/0x15c
LR is at musb_h_disable+0xfc/0x15c
pc : []lr : []psr: 60070093
sp : d3e5bc80  ip : 0027  fp : d3e5bca4
r10:   r9 : ff94  r8 : 0080
r7 : 60070013  r6 : d45900f0  r5 : d4717720  r4 : cee2d860
r3 :   r2 : c0875628  r1 : d3e5bbc0  r0 : 002a
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 18c53c7d  Table: b3eb404a  DAC: 0015
[] (__dabt_svc+0x70/0xa0) from [] 
(musb_h_disable+0xfc/0x15c)
[] (musb_h_disable+0xfc/0x15c) from [] 
(usb_hcd_disable_endpoint+0x3c/0x44)
[] (usb_hcd_disable_endpoint+0x3c/0x44) from [] 
(usb_disable_endpoint+0x64/0x7c)
[] (usb_disable_endpoint+0x64/0x7c) from [] 
(usb_disable_interface+0x48/0x58)
[] (usb_disable_interface+0x48/0x58) from [] 
(usb_set_interface+0x158/0x274)
[] (usb_set_interface+0x158/0x274) from [] 
(uvc_video_enable+0x78/0x9c)
[] (uvc_video_enable+0x78/0x9c) from [] 
(uvc_v4l2_do_ioctl+0xd08/0x12ec)
[] (uvc_v4l2_do_ioctl+0xd08/0x12ec) from [] 
(video_usercopy+0x144/0x500)
[] (video_usercopy+0x144/0x500) from [] 
(uvc_v4l2_ioctl+0x2c/0x74)
[] (uvc_v4l2_ioctl+0x2c/0x74) from [] 
(v4l2_ioctl+0x94/0x154)
[] (v4l2_ioctl+0x94/0x154) from [] (do_vfs_ioctl+0x84/0x5ac)
[] (do_vfs_ioctl+0x84/0x5ac) from [] (sys_ioctl+0x78/0x80)
[] (sys_ioctl+0x78/0x80) from [] (ret_fast_syscall+0x0/0x30)

Considering the following execution sequence:
CPU0   CPU1
musb_urb_dequeue
 spin_lock_irqsave(>lock, flags);
  ready = qh->is_ready;
   qh->is_ready = 0;
musb_giveback(musb, urb, 0);
 spin_unlock(>lock);
   zx296702_musb_interrupt
musb_interrupt
 spin_lock_irqsave(>lock, flags);
  musb_advance_schedule
   ready = qh->is_ready;
qh->is_ready = 0;
 musb_giveback(musb, urb, status);
  spin_unlock(>lock);
  spin_lock(>lock);
   qh->is_ready = ready;
spin_unlock_irqrestore(>lock, flags);
   spin_lock(>lock);
qh->is_ready = ready;

When musb_urb_dequeue is called finally, the qh->is_ready has already
been set to 0 in error.Thus the recycling qh job in musb_urb_dequeue
can not be done. That results in accessing empty qh in musb_h_disable.
So the qh in musb_h_disable should be checked.If the qh is emtpy,
then recycle it and go to exit directly.

---
v2:
 - Modify the urb empty condition
---

Signed-off-by: Liu Xiang <liu.xia...@zte.com.cn>
---
 drivers/usb/musb/musb_host.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 795a45b..8445db3 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2515,7 +2515,12 @@ musb_h_disable(struct usb_hcd *hcd, struct 
usb_host_endpoint *hep)
qh->is_ready = 0;
if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
urb = next_urb(qh);
-
+   if (!urb) {
+   qh->hep->hcpriv = NULL;
+   list_del(>ring);
+   kfree(qh);
+   goto exit;
+   }
/* make software (then hardware) stop ASAP */
if (!urb->unlinked)
urb->status = -ESHUTDOWN;
-- 
1.9.1


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[PATCH] usb: musb: host: Fix NULL pointer dereference in SMP environment

2016-02-19 Thread Liu Xiang

In multi-core SoC, if enable USB endpoint/transmit urb/disable 
USB endpoint repeatedly,it can cause a NULL pointer dereference bug:

Unable to handle kernel NULL pointer dereference at virtual address 0010
pgd = d3eb4000
[0010] *pgd=
Internal error: Oops: 5 [#1] PREEMPT SMP
Pid: 1017, comm:  mediaserver
CPU: 0Not tainted  (3.0.101-ZXICTOS_V2.00.20_P2B4_ZTE_ZX296700_ASIC+ #2)
PC is at musb_h_disable+0xfc/0x15c
LR is at musb_h_disable+0xfc/0x15c
pc : []lr : []psr: 60070093
sp : d3e5bc80  ip : 0027  fp : d3e5bca4
r10:   r9 : ff94  r8 : 0080
r7 : 60070013  r6 : d45900f0  r5 : d4717720  r4 : cee2d860
r3 :   r2 : c0875628  r1 : d3e5bbc0  r0 : 002a
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 18c53c7d  Table: b3eb404a  DAC: 0015
[] (__dabt_svc+0x70/0xa0) from [] 
(musb_h_disable+0xfc/0x15c)
[] (musb_h_disable+0xfc/0x15c) from [] 
(usb_hcd_disable_endpoint+0x3c/0x44)
[] (usb_hcd_disable_endpoint+0x3c/0x44) from [] 
(usb_disable_endpoint+0x64/0x7c)
[] (usb_disable_endpoint+0x64/0x7c) from [] 
(usb_disable_interface+0x48/0x58)
[] (usb_disable_interface+0x48/0x58) from [] 
(usb_set_interface+0x158/0x274)
[] (usb_set_interface+0x158/0x274) from [] 
(uvc_video_enable+0x78/0x9c)
[] (uvc_video_enable+0x78/0x9c) from [] 
(uvc_v4l2_do_ioctl+0xd08/0x12ec)
[] (uvc_v4l2_do_ioctl+0xd08/0x12ec) from [] 
(video_usercopy+0x144/0x500)
[] (video_usercopy+0x144/0x500) from [] 
(uvc_v4l2_ioctl+0x2c/0x74)
[] (uvc_v4l2_ioctl+0x2c/0x74) from [] 
(v4l2_ioctl+0x94/0x154)
[] (v4l2_ioctl+0x94/0x154) from [] (do_vfs_ioctl+0x84/0x5ac)
[] (do_vfs_ioctl+0x84/0x5ac) from [] (sys_ioctl+0x78/0x80)
[] (sys_ioctl+0x78/0x80) from [] (ret_fast_syscall+0x0/0x30)

Considering the following execution sequence:
CPU0   CPU1
musb_urb_dequeue
 spin_lock_irqsave(>lock, flags);
  ready = qh->is_ready;
   qh->is_ready = 0;
musb_giveback(musb, urb, 0);
 spin_unlock(>lock);
   zx296702_musb_interrupt
musb_interrupt
 spin_lock_irqsave(>lock, flags);
  musb_advance_schedule
   ready = qh->is_ready;
qh->is_ready = 0;
 musb_giveback(musb, urb, status);
  spin_unlock(>lock);
  spin_lock(>lock);
   qh->is_ready = ready;
spin_unlock_irqrestore(>lock, flags);
   spin_lock(>lock);
qh->is_ready = ready;

When musb_urb_dequeue is called finally, the qh->is_ready has already 
been set to 0 in error.Thus the recycling qh job in musb_urb_dequeue 
can not be done. That results in accessing empty qh in musb_h_disable.
So the qh in musb_h_disable should be checked.If the qh is emtpy, 
then recycle it and go to exit directly.

Signed-off-by: Liu Xiang <liu.xia...@zte.com.cn>
---
 drivers/usb/musb/musb_host.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 795a45b..438f5b4 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2515,7 +2515,12 @@ musb_h_disable(struct usb_hcd *hcd, struct 
usb_host_endpoint *hep)
qh->is_ready = 0;
if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
urb = next_urb(qh);
-
+   if (urb == NULL) {
+   qh->hep->hcpriv = NULL;
+   list_del(>ring);
+   kfree(qh);
+   goto exit;
+   }
/* make software (then hardware) stop ASAP */
if (!urb->unlinked)
urb->status = -ESHUTDOWN;
-- 
1.9.1


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[PATCH v2] usb: musb: host: Fix NULL pointer dereference in SMP environment

[PATCH] usb: musb: host: Fix NULL pointer dereference in SMP environment

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