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2f588cee24
linux/drivers/tty
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Dmitry Safonov 2f588cee24 tty/ldsem: Decrement wait_readers on timeouted down_read() 
It seems like when ldsem_down_read() fails with timeout, it misses
update for sem->wait_readers. By that reason, when writer finally
releases write end of the semaphore __ldsem_wake_readers() does adjust
sem->count with wrong value:
sem->wait_readers * (LDSEM_ACTIVE_BIAS - LDSEM_WAIT_BIAS)

I.e, if update comes with 1 missed wait_readers decrement, sem->count
will be 0x100000001 which means that there is active reader and it'll
make any further writer to fail in acquiring the semaphore.

It looks like, this is a dead-code, because ldsem_down_read() is never
called with timeout different than MAX_SCHEDULE_TIMEOUT, so it might be
worth to delete timeout parameter and error path fall-back..

Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05 12:16:33 +01:00
..
hvc tty: hvc: hvc_write() fix break condition 2018-09-10 18:04:31 +02:00
ipwireless ipwireless: switch to ->[sg]et_serial() 2018-10-13 00:50:31 -04:00
serdev serdev: document the write functions using kernel-doc 2018-11-27 19:44:21 +01:00
serial serial: 8250-mtk: add uart DMA support 2018-12-05 11:02:39 +01:00
vt TTY/Serial fixes for 4.20-rc2 2018-11-10 13:32:14 -06:00
amiserial.c kill TIOCSERGSTRUCT 2018-10-13 00:50:53 -04:00
cyclades.c cyclades: switch to ->[sg]et_serial() 2018-10-13 00:50:30 -04:00
ehv_bytechan.c tty: Convert to using %pOFn instead of device_node.name 2018-09-18 16:07:25 +02:00
goldfish.c headers: separate linux/mod_devicetable.h from linux/platform_device.h 2018-07-07 17:52:26 +02:00
isicom.c isicom: switch to ->[sg]et_serial() 2018-10-13 00:50:31 -04:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-04-09 09:04:10 -07:00
Makefile tty: remove bfin_jtag_comm and hvc_bfin_jtag drivers 2018-03-26 15:57:24 +02:00
mips_ejtag_fdc.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
moxa.c moxa: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
moxa.h tty: moxa: Add support for CMSPAR 2017-11-28 15:32:33 +01:00
mxser.c mxser: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
mxser.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
n_gsm.c change semantics of ldisc ->compat_ioctl() 2018-10-13 00:50:53 -04:00
n_hdlc.c tty: Don't block on IO when ldisc change is pending 2018-12-05 12:16:33 +01:00
n_null.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_r3964.c tty: Don't block on IO when ldisc change is pending 2018-12-05 12:16:33 +01:00
n_tracerouter.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tracesink.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tracesink.h tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tty.c tty: Don't block on IO when ldisc change is pending 2018-12-05 12:16:33 +01:00
nozomi.c tty/nozomi: fix inconsistent indentation 2018-04-25 14:54:26 +02:00
pty.c pty: fix compat ioctls 2018-10-13 00:50:51 -04:00
rocket_int.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rocket.c tty: rocket: Fix possible buffer overwrite on register_PCI 2018-08-02 10:11:32 +02:00
rocket.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
synclink_gt.c synclink_gt(): fix compat_ioctl() 2018-10-13 00:50:52 -04:00
synclink.c synclink: reduce pointless checks in ->ioctl() 2018-10-13 00:50:43 -04:00
synclinkmp.c synclink: reduce pointless checks in ->ioctl() 2018-10-13 00:50:43 -04:00
sysrq.c tty/sysrq: Do not call sync directly from sysrq_do_reset() 2018-12-05 12:02:12 +01:00
tty_audit.c audit: eliminate audit_enabled magic number comparison 2018-06-19 10:43:55 -04:00
tty_baudrate.c termios, tty/tty_baudrate.c: fix buffer overrun 2018-11-08 03:36:45 -08:00
tty_buffer.c tty: wipe buffer. 2018-10-11 19:50:00 +02:00
tty_io.c tty: Simplify tty->count math in tty_reopen() 2018-12-05 12:16:33 +01:00
tty_ioctl.c move compat handling of tty ioctls to tty_compat_ioctl() 2018-09-14 11:12:17 -04:00
tty_jobctrl.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_ldisc.c tty/ldsem: Add lockdep asserts for ldisc_sem 2018-12-05 12:16:33 +01:00
tty_ldsem.c tty/ldsem: Decrement wait_readers on timeouted down_read() 2018-12-05 12:16:33 +01:00
tty_mutex.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tty_port.c tty_port: Remove incorrect whitespace after comments 2018-09-18 16:07:25 +02:00
vcc.c tty: vcc: Convert timers to use timer_setup() 2017-11-04 12:01:54 +01:00