Re: [PATCH 00/12] Rework tty_reopen()
On Wed, Dec 16, 2015 at 07:43:11AM -0800, Peter Hurley wrote: > Hi Greg, > > This series has been reported to fix a regression with Redhat's kdump > systemd service redirecting to /dev/console, when /dev/console is a > serial port. > > The redirection consistently fails with EIO since > "tty: Remove tty_wait_until_sent_from_close", which is new to 4.4-rc > Prior to that patch, redirection would only occasionally fail with EIO. :) > > [ The systemd repeated hangup of /dev/console also seems to be the > [ trigger for the serial driver crashes on hangup as well, which is > [ fixed by the 19-patch "Fix driver crashes on hangup" series. > [ That problem goes back to 3.10, but has only been reported recently, > [ which leads me to believe recent changes in systemd /dev/console > [ handling is a contributing factor (which I'm checking right now) > > Here are what I think are the options to resolve the regression: > > #1. Respin this series w/o the tty-next dependencies > #2. Split this series into the minimum necessary to fix the regression > #3. Revert from 4.4-rc (in revert order) > "tty: Remove wait_event_interruptible_tty()" > "tty: r3964: Replace/remove bogus tty lock use" > "tty: r3964: Use tty->read_wait waitqueue" > "tty: Remove tty_port::close_wait" > "usb: gadget: gserial: Privatize close_wait" > "tty: Remove ASYNC_CLOSING check in open()/hangup() methods" > "tty: Remove tty_wait_until_sent_from_close()" > > Let me know how you'd like me to handle this. Sounds like a reasonable approach, send the patches on and let's see what they look like. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 00/12] Rework tty_reopen()
On 16/12/2015:07:43:11 AM, Peter Hurley wrote: > #1. Respin this series w/o the tty-next dependencies > #2. Split this series into the minimum necessary to fix the regression As far as kdump issue is concerned, backporting only 12/12 to 4.4-RC is able to resolve it. ~Pratyush -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 00/12] Rework tty_reopen()
Hi Greg, This series has been reported to fix a regression with Redhat's kdump systemd service redirecting to /dev/console, when /dev/console is a serial port. The redirection consistently fails with EIO since "tty: Remove tty_wait_until_sent_from_close", which is new to 4.4-rc Prior to that patch, redirection would only occasionally fail with EIO. :) [ The systemd repeated hangup of /dev/console also seems to be the [ trigger for the serial driver crashes on hangup as well, which is [ fixed by the 19-patch "Fix driver crashes on hangup" series. [ That problem goes back to 3.10, but has only been reported recently, [ which leads me to believe recent changes in systemd /dev/console [ handling is a contributing factor (which I'm checking right now) Here are what I think are the options to resolve the regression: #1. Respin this series w/o the tty-next dependencies #2. Split this series into the minimum necessary to fix the regression #3. Revert from 4.4-rc (in revert order) "tty: Remove wait_event_interruptible_tty()" "tty: r3964: Replace/remove bogus tty lock use" "tty: r3964: Use tty->read_wait waitqueue" "tty: Remove tty_port::close_wait" "usb: gadget: gserial: Privatize close_wait" "tty: Remove ASYNC_CLOSING check in open()/hangup() methods" "tty: Remove tty_wait_until_sent_from_close()" Let me know how you'd like me to handle this. Sorry, Peter Hurley On 11/27/2015 06:25 PM, Peter Hurley wrote: > This patch series implements two important improvements to tty open() > behavior: interruptible open() and automatic retry when tty teardown > has already commenced. > > Interruptible open() allows signals to cancel the open wait if stalled > waiting for tty teardown to complete. > > Automatic retry of tty open() when racing a tty teardown now makes tty > open() fully POSIX compliant. For some time, the Linux kernel has > returned EIO from open() under certain circumstances. This happens when > tty_open() observes a valid tty from driver lookup but the tty is > being released (in final close) and teardown is about to commence. > > The observable userspace change is that userspace will no longer need > to retry open() on EIO error. > > This series also continues the ongoing effort to cleanup and reduce the > kernel tty interface. > > Lastly, this series lays important groundwork for implementing ptmx_open() > in tty_open(), trivially with driver lookup (still a work-in-progress). > > Regards, > > Peter Hurley (12): > tty: Fix ldisc leak in failed tty_init_dev() > tty: Remove !tty check from free_tty_struct() > tty: Fix tty_init_termios() declaration > tty: Re-declare tty_driver_remove_tty() file scope > pty: Remove pty_unix98_shutdown() > tty: Remove __lockfunc annotation from tty lock functions > tty: Wait interruptibly for tty lock on reopen > pty: Prepare to redefine tty driver remove() interface > tty: Re-define tty driver remove() interface > tty: Consolidate noctty checks in tty_open() > tty: Refactor tty_open() > tty: Retry failed reopen if tty teardown in-progress > > drivers/tty/pty.c| 40 +++--- > drivers/tty/tty_io.c | 180 > +-- > drivers/tty/tty_ldisc.c | 21 +++-- > drivers/tty/tty_mutex.c | 16 +++- > drivers/usb/serial/console.c | 6 +- > include/linux/tty.h | 19 ++--- > include/linux/tty_driver.h | 4 +- > 7 files changed, 128 insertions(+), 158 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 00/12] Rework tty_reopen()
On 16/12/2015:07:43:11 AM, Peter Hurley wrote: > #1. Respin this series w/o the tty-next dependencies > #2. Split this series into the minimum necessary to fix the regression As far as kdump issue is concerned, backporting only 12/12 to 4.4-RC is able to resolve it. ~Pratyush -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 00/12] Rework tty_reopen()
On Wed, Dec 16, 2015 at 07:43:11AM -0800, Peter Hurley wrote: > Hi Greg, > > This series has been reported to fix a regression with Redhat's kdump > systemd service redirecting to /dev/console, when /dev/console is a > serial port. > > The redirection consistently fails with EIO since > "tty: Remove tty_wait_until_sent_from_close", which is new to 4.4-rc > Prior to that patch, redirection would only occasionally fail with EIO. :) > > [ The systemd repeated hangup of /dev/console also seems to be the > [ trigger for the serial driver crashes on hangup as well, which is > [ fixed by the 19-patch "Fix driver crashes on hangup" series. > [ That problem goes back to 3.10, but has only been reported recently, > [ which leads me to believe recent changes in systemd /dev/console > [ handling is a contributing factor (which I'm checking right now) > > Here are what I think are the options to resolve the regression: > > #1. Respin this series w/o the tty-next dependencies > #2. Split this series into the minimum necessary to fix the regression > #3. Revert from 4.4-rc (in revert order) > "tty: Remove wait_event_interruptible_tty()" > "tty: r3964: Replace/remove bogus tty lock use" > "tty: r3964: Use tty->read_wait waitqueue" > "tty: Remove tty_port::close_wait" > "usb: gadget: gserial: Privatize close_wait" > "tty: Remove ASYNC_CLOSING check in open()/hangup() methods" > "tty: Remove tty_wait_until_sent_from_close()" > > Let me know how you'd like me to handle this. Sounds like a reasonable approach, send the patches on and let's see what they look like. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 00/12] Rework tty_reopen()
Hi Greg, This series has been reported to fix a regression with Redhat's kdump systemd service redirecting to /dev/console, when /dev/console is a serial port. The redirection consistently fails with EIO since "tty: Remove tty_wait_until_sent_from_close", which is new to 4.4-rc Prior to that patch, redirection would only occasionally fail with EIO. :) [ The systemd repeated hangup of /dev/console also seems to be the [ trigger for the serial driver crashes on hangup as well, which is [ fixed by the 19-patch "Fix driver crashes on hangup" series. [ That problem goes back to 3.10, but has only been reported recently, [ which leads me to believe recent changes in systemd /dev/console [ handling is a contributing factor (which I'm checking right now) Here are what I think are the options to resolve the regression: #1. Respin this series w/o the tty-next dependencies #2. Split this series into the minimum necessary to fix the regression #3. Revert from 4.4-rc (in revert order) "tty: Remove wait_event_interruptible_tty()" "tty: r3964: Replace/remove bogus tty lock use" "tty: r3964: Use tty->read_wait waitqueue" "tty: Remove tty_port::close_wait" "usb: gadget: gserial: Privatize close_wait" "tty: Remove ASYNC_CLOSING check in open()/hangup() methods" "tty: Remove tty_wait_until_sent_from_close()" Let me know how you'd like me to handle this. Sorry, Peter Hurley On 11/27/2015 06:25 PM, Peter Hurley wrote: > This patch series implements two important improvements to tty open() > behavior: interruptible open() and automatic retry when tty teardown > has already commenced. > > Interruptible open() allows signals to cancel the open wait if stalled > waiting for tty teardown to complete. > > Automatic retry of tty open() when racing a tty teardown now makes tty > open() fully POSIX compliant. For some time, the Linux kernel has > returned EIO from open() under certain circumstances. This happens when > tty_open() observes a valid tty from driver lookup but the tty is > being released (in final close) and teardown is about to commence. > > The observable userspace change is that userspace will no longer need > to retry open() on EIO error. > > This series also continues the ongoing effort to cleanup and reduce the > kernel tty interface. > > Lastly, this series lays important groundwork for implementing ptmx_open() > in tty_open(), trivially with driver lookup (still a work-in-progress). > > Regards, > > Peter Hurley (12): > tty: Fix ldisc leak in failed tty_init_dev() > tty: Remove !tty check from free_tty_struct() > tty: Fix tty_init_termios() declaration > tty: Re-declare tty_driver_remove_tty() file scope > pty: Remove pty_unix98_shutdown() > tty: Remove __lockfunc annotation from tty lock functions > tty: Wait interruptibly for tty lock on reopen > pty: Prepare to redefine tty driver remove() interface > tty: Re-define tty driver remove() interface > tty: Consolidate noctty checks in tty_open() > tty: Refactor tty_open() > tty: Retry failed reopen if tty teardown in-progress > > drivers/tty/pty.c| 40 +++--- > drivers/tty/tty_io.c | 180 > +-- > drivers/tty/tty_ldisc.c | 21 +++-- > drivers/tty/tty_mutex.c | 16 +++- > drivers/usb/serial/console.c | 6 +- > include/linux/tty.h | 19 ++--- > include/linux/tty_driver.h | 4 +- > 7 files changed, 128 insertions(+), 158 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
