| Message ID | 1411966997-27118-10-git-send-email-r65037@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Am Montag, den 29.09.2014, 13:03 +0800 schrieb Richard Zhu: > kernel report one possible dead lock during imx6sx pcie > suspend resume stress tests, after enable Lock Debugging. > platform: imx6sx sdb board + xhci(pcie2usb3.0 ep) > > reason: usleep_range used in imx6_pcie_link_up maybe scheduled > out from dw_pcie_valid_config.isra... > About details, please see the following logs. > > solution: replace the usleep_range(1000, 2000) by udelay(10) and > enlarge the loop counter. > I don't like this change, as we eat one CPU just to work around a slightly wrong behavior of the link-up signaling. I had a look at the code in question and it seems there are more things that need different handling in there. I'll post a patch to resolve the deadlock without using a udelay shortly. Regards, Lucas > logs: > [ 50.643062] xhci_hcd 0000:01:00.0: Refused to change power state, currently in D3 > [ 50.653390] > [ 50.654898] ========================================================= > [ 50.661343] [ INFO: possible irq lock inversion dependency detected ] > [ 50.667792] 3.17.0-rc2-01341-gfc43ff7-dirty #101 Not tainted > [ 50.673454] --------------------------------------------------------- > [ 50.679898] kworker/u2:2/48 just changed the state of lock: > [ 50.685477] (pci_lock){+.....}, at: [<802d650c>] pci_bus_read_config_dword+0x44/0x94 > [ 50.693394] but this lock was taken by another, HARDIRQ-safe lock in the past: > [ 50.700619] (&irq_desc_lock_class){-.-...} > > and interrupts could create inverse lock ordering between them. > > [ 50.710843] > [ 50.710843] other info that might help us debug this: > [ 50.717377] Possible interrupt unsafe locking scenario: > [ 50.717377] > [ 50.724169] CPU0 CPU1 > [ 50.728702] ---- ---- > [ 50.733234] lock(pci_lock); > [ 50.736232] local_irq_disable(); > [ 50.742154] lock(&irq_desc_lock_class); > [ 50.748713] lock(pci_lock); > [ 50.754229] <Interrupt> > [ 50.756852] lock(&irq_desc_lock_class); > [ 50.761065] > [ 50.761065] *** DEADLOCK *** > ... > > [ 52.119515] [<806e8ad0>] (schedule_hrtimeout_range) from [<80077e90>] (usleep_range+0x50/0x58) > [ 52.128141] [<80077e40>] (usleep_range) from [<802f3694>] (imx6_pcie_link_up+0x48/0x16c) > [ 52.136242] [<802f364c>] (imx6_pcie_link_up) from [<802f1b74>] (dw_pcie_valid_config.isra.10+0x40/0x7c) > [ 52.145637] r6:ae72606d r5:ae72606c r4:ae711228 > [ 52.150311] [<802f1b34>] (dw_pcie_valid_config.isra.10) from [<802f1ca8>] (dw_pcie_rd_conf+0x4c/0x154) > [ 52.159620] r7:00000000 r6:00000000 r5:ae711228 r4:ae726000 > [ 52.165355] [<802f1c5c>] (dw_pcie_rd_conf) from [<802d6534>] (pci_bus_read_config_dword+0x6c/0x94) > [ 52.174316] r9:adf4e910 r8:809bc51c r7:00000000 r6:60000153 r5:adc3fd5c r4:ae726000 > [ 52.182152] [<802d64c8>] (pci_bus_read_config_dword) from [<802db588>] (pci_restore_config_dword+0x54/0xa4) > [ 52.191894] r6:00000024 r5:0000000a r4:ae61e000 > [ 52.196570] [<802db534>] (pci_restore_config_dword) from [<802dd150>] (pci_restore_state.part.37+0x7c/0x1f8) > [ 52.206399] r8:802e086c r7:ae61dfe8 r6:519e2024 r5:ae61e000 r4:ae61dffc > [ 52.213187] [<802dd0d4>] (pci_restore_state.part.37) from [<802dd2e8>] (pci_restore_state+0x1c/0x20) > [ 52.222322] r7:adc3fea8 r6:809d90e0 r5:ae61e000 r4:ae61e068 > [ 52.228056] [<802dd2cc>] (pci_restore_state) from [<802e0894>] (pci_pm_resume_noirq+0x28/0xa4) > [ 52.236683] [<802e086c>] (pci_pm_resume_noirq) from [<8037ea1c>] (dpm_run_callback.isra.12+0x34/0x7c) > > Signed-off-by: Richard Zhu <r65037@freescale.com> > --- > drivers/pci/host/pci-imx6.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c > index be953aa..e60c195 100644 > --- a/drivers/pci/host/pci-imx6.c > +++ b/drivers/pci/host/pci-imx6.c > @@ -521,7 +521,7 @@ static void imx6_pcie_reset_phy(struct pcie_port *pp) > static int imx6_pcie_link_up(struct pcie_port *pp) > { > u32 rc, debug_r0, rx_valid; > - int count = 5; > + int count = 500; > > /* > * Test if the PHY reports that the link is up and also that the LTSSM > @@ -552,7 +552,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp) > * Wait a little bit, then re-check if the link finished > * the training. > */ > - usleep_range(1000, 2000); > + udelay(10); > } > /* > * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index be953aa..e60c195 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -521,7 +521,7 @@ static void imx6_pcie_reset_phy(struct pcie_port *pp) static int imx6_pcie_link_up(struct pcie_port *pp) { u32 rc, debug_r0, rx_valid; - int count = 5; + int count = 500; /* * Test if the PHY reports that the link is up and also that the LTSSM @@ -552,7 +552,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp) * Wait a little bit, then re-check if the link finished * the training. */ - usleep_range(1000, 2000); + udelay(10); } /* * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
kernel report one possible dead lock during imx6sx pcie suspend resume stress tests, after enable Lock Debugging. platform: imx6sx sdb board + xhci(pcie2usb3.0 ep) reason: usleep_range used in imx6_pcie_link_up maybe scheduled out from dw_pcie_valid_config.isra... About details, please see the following logs. solution: replace the usleep_range(1000, 2000) by udelay(10) and enlarge the loop counter. logs: [ 50.643062] xhci_hcd 0000:01:00.0: Refused to change power state, currently in D3 [ 50.653390] [ 50.654898] ========================================================= [ 50.661343] [ INFO: possible irq lock inversion dependency detected ] [ 50.667792] 3.17.0-rc2-01341-gfc43ff7-dirty #101 Not tainted [ 50.673454] --------------------------------------------------------- [ 50.679898] kworker/u2:2/48 just changed the state of lock: [ 50.685477] (pci_lock){+.....}, at: [<802d650c>] pci_bus_read_config_dword+0x44/0x94 [ 50.693394] but this lock was taken by another, HARDIRQ-safe lock in the past: [ 50.700619] (&irq_desc_lock_class){-.-...} and interrupts could create inverse lock ordering between them. [ 50.710843] [ 50.710843] other info that might help us debug this: [ 50.717377] Possible interrupt unsafe locking scenario: [ 50.717377] [ 50.724169] CPU0 CPU1 [ 50.728702] ---- ---- [ 50.733234] lock(pci_lock); [ 50.736232] local_irq_disable(); [ 50.742154] lock(&irq_desc_lock_class); [ 50.748713] lock(pci_lock); [ 50.754229] <Interrupt> [ 50.756852] lock(&irq_desc_lock_class); [ 50.761065] [ 50.761065] *** DEADLOCK *** ... [ 52.119515] [<806e8ad0>] (schedule_hrtimeout_range) from [<80077e90>] (usleep_range+0x50/0x58) [ 52.128141] [<80077e40>] (usleep_range) from [<802f3694>] (imx6_pcie_link_up+0x48/0x16c) [ 52.136242] [<802f364c>] (imx6_pcie_link_up) from [<802f1b74>] (dw_pcie_valid_config.isra.10+0x40/0x7c) [ 52.145637] r6:ae72606d r5:ae72606c r4:ae711228 [ 52.150311] [<802f1b34>] (dw_pcie_valid_config.isra.10) from [<802f1ca8>] (dw_pcie_rd_conf+0x4c/0x154) [ 52.159620] r7:00000000 r6:00000000 r5:ae711228 r4:ae726000 [ 52.165355] [<802f1c5c>] (dw_pcie_rd_conf) from [<802d6534>] (pci_bus_read_config_dword+0x6c/0x94) [ 52.174316] r9:adf4e910 r8:809bc51c r7:00000000 r6:60000153 r5:adc3fd5c r4:ae726000 [ 52.182152] [<802d64c8>] (pci_bus_read_config_dword) from [<802db588>] (pci_restore_config_dword+0x54/0xa4) [ 52.191894] r6:00000024 r5:0000000a r4:ae61e000 [ 52.196570] [<802db534>] (pci_restore_config_dword) from [<802dd150>] (pci_restore_state.part.37+0x7c/0x1f8) [ 52.206399] r8:802e086c r7:ae61dfe8 r6:519e2024 r5:ae61e000 r4:ae61dffc [ 52.213187] [<802dd0d4>] (pci_restore_state.part.37) from [<802dd2e8>] (pci_restore_state+0x1c/0x20) [ 52.222322] r7:adc3fea8 r6:809d90e0 r5:ae61e000 r4:ae61e068 [ 52.228056] [<802dd2cc>] (pci_restore_state) from [<802e0894>] (pci_pm_resume_noirq+0x28/0xa4) [ 52.236683] [<802e086c>] (pci_pm_resume_noirq) from [<8037ea1c>] (dpm_run_callback.isra.12+0x34/0x7c) Signed-off-by: Richard Zhu <r65037@freescale.com> --- drivers/pci/host/pci-imx6.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)