On Fri, 18 Jan 2013, Roger Quadros wrote:
> Thanks. I used the below code (also attached) and could reproduce
> corruption on the first byte at ehci->priv. This is from the the kernel log.
>
> > [ 30.381774] ehci-omap ehci-omap.0: ehci_hcd_omap_probe a 0x1234abcd, b 0x5679efba
>
> > [ 122.523468] ehci-omap ehci-omap.0: ehci_hcd_omap_remove a 0x1234abe0, b 0x5679efba
>
> NOTE: EHCI needs to be running and you need to enumerate some device for
> the corruption to happen.
>
> If I disable CONFIG_USB_DEBUG, then there is no corruption.
I tried doing something similar with (using ehci-pci rather than
ehci-omap) and didn't get any corruption. My test patch is below.
Unforunately you won't be able to utilize the hw_breakpoint mechanism
in your testing because it hasn't been set up for OMAP. Here's the log
for a test with two EHCI controllers and one device plugged in. (Note:
I did have CONFIG_USB_DEBUG enabled, but this log doesn't include any
of the debug-level messages.)
[ 1217.550517] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 1220.650589] ehci-pci: EHCI PCI platform driver
[ 1220.658534] ehci-pci 0000:00:1d.7: EHCI Host Controller
[ 1220.662595] ehci-pci 0000:00:1d.7: new USB bus registered, assigned bus number 1
[ 1220.680773] Breakpoint at e993a868 was hit!
[ 1220.683678] Pid: 2853, comm: modprobe Tainted: G O 3.7.0AS-00240-g4e405e8-dirty #17
[ 1220.684016] Call Trace:
[ 1220.684016] [<c102387b>] ? console_unlock+0x323/0x34c
[ 1220.684016] [<f0034137>] ? ehci_hrtimer_func+0xa6/0xa6 [ehci_hcd]
[ 1220.684016] [<f003414f>] ehci_hbp_handler+0x18/0x1c [ehci_hcd]
[ 1220.684016] [<c106f17f>] __perf_event_overflow+0x183/0x1fb
[ 1220.684016] [<c106f33c>] perf_swevent_overflow+0x40/0x5e
[ 1220.684016] [<c106f41d>] perf_swevent_event+0xc3/0xcd
[ 1220.684016] [<c106faf9>] perf_bp_event+0x86/0x8f
[ 1220.684016] [<c10566b5>] ? __lock_acquire+0xc5b/0xc6a
[ 1220.684016] [<c10522db>] ? tick_program_event+0x1f/0x24
[ 1220.684016] [<c123405b>] hw_breakpoint_exceptions_notify+0xec/0x17a
[ 1220.684016] [<c12350d2>] notifier_call_chain+0x51/0x7a
[ 1220.684016] [<c123512d>] __atomic_notifier_call_chain+0x32/0x56
[ 1220.684016] [<c123515d>] atomic_notifier_call_chain+0xc/0xe
[ 1220.684016] [<c123518c>] notify_die+0x2d/0x2f
[ 1220.684016] [<c12336cd>] do_debug+0x69/0x11b
[ 1220.684016] [<c12332e9>] debug_stack_correct+0x2e/0x35
[ 1220.684016] [<f003007b>] ? single_unlink_async+0xc/0x5d [ehci_hcd]
[ 1220.684016] [<f0037633>] ? ehci_setup+0x64d/0x6aa [ehci_hcd]
[ 1220.684016] [<c100502a>] ? dma_set_mask+0x41/0x41
[ 1220.684016] [<eff742a3>] ehci_pci_setup+0x2a3/0x498 [ehci_pci]
[ 1220.684016] [<effe7643>] usb_add_hcd+0x18c/0x5a5 [usbcore]
[ 1220.684016] [<efff26a7>] usb_hcd_pci_probe+0x1d3/0x2d8 [usbcore]
[ 1220.684016] [<c1145ff3>] pci_device_probe+0x7c/0xd9
[ 1220.684016] [<c119629d>] driver_probe_device+0x8b/0x168
[ 1220.684016] [<c11963c4>] __driver_attach+0x4a/0x66
[ 1220.684016] [<c119503e>] bus_for_each_dev+0x3f/0x61
[ 1220.684016] [<c1195fd3>] driver_attach+0x17/0x1c
[ 1220.684016] [<c119637a>] ? driver_probe_device+0x168/0x168
[ 1220.684016] [<c1195ba3>] bus_add_driver+0x8e/0x1b4
[ 1220.684016] [<c11967a8>] driver_register+0x72/0xdd
[ 1220.684016] [<c1138107>] ? __raw_spin_lock_init+0x26/0x48
[ 1220.684016] [<c11460e5>] __pci_register_driver+0x45/0x48
[ 1220.684016] [<eff79059>] ehci_pci_init+0x59/0x1000 [ehci_pci]
[ 1220.684016] [<c1001183>] do_one_initcall+0x71/0x11a
[ 1220.684016] [<eff79000>] ? 0xeff78fff
[ 1220.684016] [<c105e01f>] sys_init_module+0x1354/0x1516
[ 1220.684016] [<c1054e98>] ? trace_hardirqs_on_caller+0x13f/0x17e
[ 1220.684016] [<c12366fe>] sysenter_do_call+0x12/0x36
[ 1220.796643] ehci-pci 0000:00:1d.7: ehci_setup a 1238abcf b 5679efba
[ 1220.799409] ehci-pci 0000:00:1d.7: debug port 1
[ 1220.807738] ehci-pci 0000:00:1d.7: irq 23, io mem 0xfe77bc00
[ 1220.824062] ehci-pci 0000:00:1d.7: USB 2.0 started, EHCI 1.00
[ 1220.835340] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[ 1220.838733] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 1220.842190] usb usb1: Product: EHCI Host Controller
[ 1220.845492] usb usb1: Manufacturer: Linux 3.7.0AS-00240-g4e405e8-dirty ehci_hcd
[ 1220.848827] usb usb1: SerialNumber: 0000:00:1d.7
[ 1220.885420] hub 1-0:1.0: USB hub found
[ 1220.889325] hub 1-0:1.0: 8 ports detected
[ 1220.940628] ehci-pci 0000:01:01.2: EHCI Host Controller
[ 1220.943363] ehci-pci 0000:01:01.2: new USB bus registered, assigned bus number 2
[ 1220.975320] ehci-pci 0000:01:01.2: ehci_setup a 1238abcf b 5679efba
[ 1220.985385] ehci-pci 0000:01:01.2: irq 9, io mem 0xfe5dfc00
[ 1221.000070] ehci-pci 0000:01:01.2: USB 2.0 started, EHCI 1.00
[ 1221.011691] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002
[ 1221.015403] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 1221.018738] usb usb2: Product: EHCI Host Controller
[ 1221.026111] usb usb2: Manufacturer: Linux 3.7.0AS-00240-g4e405e8-dirty ehci_hcd
[ 1221.032874] usb usb2: SerialNumber: 0000:01:01.2
[ 1221.071590] hub 2-0:1.0: USB hub found
[ 1221.075524] hub 2-0:1.0: 5 ports detected
[ 1221.264193] usb 1-8: new high-speed USB device number 2 using ehci-pci
[ 1221.410369] usb 1-8: New USB device found, idVendor=1307, idProduct=0165
[ 1221.414050] usb 1-8: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1221.417776] usb 1-8: Product: USB Mass Storage Device
[ 1221.421381] usb 1-8: Manufacturer: USBest Technology
[ 1221.425008] usb 1-8: SerialNumber: 00000000000126
[ 1221.463177] scsi2 : usb-storage 1-8:1.0
[ 1221.483847] scsi 2:0:0:0: Direct-Access Ut165 USB2FlashStorage 0.00 PQ: 0 ANSI: 2
[ 1221.541132] sd 2:0:0:0: [sda] 7892040 512-byte logical blocks: (4.04 GB/3.76 GiB)
[ 1221.548327] sd 2:0:0:0: [sda] Write Protect is off
[ 1221.555886] sd 2:0:0:0: Attached scsi generic sg0 type 0
[ 1221.565286] sd 2:0:0:0: [sda] Asking for cache data failed
[ 1221.569781] sd 2:0:0:0: [sda] Assuming drive cache: write through
[ 1221.588258] sd 2:0:0:0: [sda] Asking for cache data failed
[ 1221.591436] sd 2:0:0:0: [sda] Assuming drive cache: write through
[ 1221.725395] sda: sda1
[ 1221.740587] sd 2:0:0:0: [sda] Asking for cache data failed
[ 1221.743764] sd 2:0:0:0: [sda] Assuming drive cache: write through
[ 1221.752126] sd 2:0:0:0: [sda] Attached SCSI removable disk
[ 1249.712922] ehci-pci 0000:01:01.2: remove, state 4
[ 1249.720586] usb usb2: USB disconnect, device number 1
[ 1249.750506] ehci-pci 0000:01:01.2: ehci_stop a 1238abcf b 5679efba
[ 1249.774435] ehci-pci 0000:01:01.2: USB bus 2 deregistered
[ 1249.779339] ehci-pci 0000:00:1d.7: remove, state 1
[ 1249.786521] usb usb1: USB disconnect, device number 1
[ 1249.790034] usb 1-8: USB disconnect, device number 2
[ 1249.914699] ehci-pci 0000:00:1d.7: ehci_stop a 1238abcf b 5679efba
[ 1249.943361] ehci-pci 0000:00:1d.7: USB bus 1 deregistered
The fact that only the first byte of ehci->priv was affected on your
system, and that it occurred only with CONFIG_USB_DEBUG, suggests that
something involving ehci->debug_dir is messing up. But that field is
assigned to in only one spot (create_debug_files), so I don't know
what's wrong.
I suppose you could try sprinkling some ehci_dbg() statements at
various strategic spots in ehci-hcd.c to narrow down where the problem
is.
Alan Stern
Index: usb-3.7/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-3.7.orig/drivers/usb/host/ehci-hcd.c
+++ usb-3.7/drivers/usb/host/ehci-hcd.c
@@ -45,10 +45,23 @@
#include <asm/irq.h>
#include <asm/unaligned.h>
+#include <linux/perf_event.h>
+#include <linux/hw_breakpoint.h>
+
+static struct perf_event * __percpu *ehci_hbp;
+static void *bp_addr;
+
#if defined(CONFIG_PPC_PS3)
#include <asm/firmware.h>
#endif
+static void ehci_hbp_handler(struct perf_event *bp,
+ struct perf_sample_data *data, struct pt_regs *regs)
+{
+ printk(KERN_INFO "Breakpoint at %p was hit!\n", bp_addr);
+ dump_stack();
+}
+
/*-------------------------------------------------------------------------*/
/*
@@ -411,9 +424,21 @@ static void ehci_work (struct ehci_hcd *
/*
* Called when the ehci_hcd module is removed.
*/
+
+struct ehci_test {
+ unsigned a, b;
+};
+
static void ehci_stop (struct usb_hcd *hcd)
{
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
+ struct ehci_test *p = (struct ehci_test *) ehci->priv;
+
+ ehci_info(ehci, "%s a %x b %x\n", __func__, p->a, p->b);
+ if (p == bp_addr) {
+ unregister_wide_hw_breakpoint(ehci_hbp);
+ bp_addr = NULL;
+ }
ehci_dbg (ehci, "stop\n");
@@ -653,6 +678,26 @@ int ehci_setup(struct usb_hcd *hcd)
{
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
int retval;
+ struct ehci_test *p = (struct ehci_test *) ehci->priv;
+
+ p->a = 0x1234abcd;
+ p->b = 0x5679efba;
+
+ if (!bp_addr) {
+ struct perf_event_attr attr;
+
+ hw_breakpoint_init(&attr);
+ attr.bp_addr = (unsigned long) p;
+ attr.bp_len = HW_BREAKPOINT_LEN_4;
+ attr.bp_type = HW_BREAKPOINT_W;
+
+ ehci_hbp = register_wide_hw_breakpoint(&attr, ehci_hbp_handler, NULL);
+ if (IS_ERR((void __force *) ehci_hbp))
+ ehci_info(ehci, "Unable to create breakpoint: %d\n",
+ (int) PTR_ERR((void __force *) ehci_hbp));
+ else
+ bp_addr = p;
+ }
ehci->regs = (void __iomem *)ehci->caps +
HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
@@ -678,6 +723,9 @@ int ehci_setup(struct usb_hcd *hcd)
ehci_reset(ehci);
+ /* Make sure the breakpoint is working */
+ p->a = 0x1238abcf;
+ ehci_info(ehci, "%s a %x b %x\n", __func__, p->a, p->b);
return 0;
}
EXPORT_SYMBOL_GPL(ehci_setup);
@@ -1236,6 +1284,7 @@ void ehci_init_driver(struct hc_driver *
if (over->reset)
drv->reset = over->reset;
}
+ drv->hcd_priv_size += sizeof(struct ehci_test);
}
EXPORT_SYMBOL_GPL(ehci_init_driver);
--
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