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7f8030d166
This patch removes the tty->low_latency setting. For irq based hvc_console backends the tty->low_latency must be set to 0, because the tty_flip_buffer_push() function must not be called from IRQ context (see drivers/char/tty_buffer.c). For polled backends, the low_latency setting causes the bug trace below, because tty_flip_buffer_push() is called within an atomic context and subsequent calls might sleep due to mutex_lock. BUG: sleeping function called from invalid context at /root/cvs/linux-2.6.git/kernel/mutex.c:207 in_atomic(): 1, irqs_disabled(): 0, pid: 748, name: khvcd 1 lock held by khvcd/748: #0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c CPU: 0 Not tainted 2.6.29-rc1git #29 Process khvcd (pid: 748, task: 000000002fb9a480, ksp: 000000002f66bd78) 070000000000000a 000000002f66ba00 0000000000000002 (null) 000000002f66baa0 000000002f66ba18 000000002f66ba18 0000000000104f08 ffffffffffffc000 000000002f66bd78 (null) (null) 000000002f66ba00 000000000000000c 000000002f66ba00 000000002f66ba70 0000000000466af8 0000000000104f08 000000002f66ba00 000000002f66ba50 Call Trace: ([<0000000000104e7c>] show_trace+0x138/0x158) [<0000000000104f62>] show_stack+0xc6/0xf8 [<0000000000105740>] dump_stack+0xb0/0xc0 [<000000000013144a>] __might_sleep+0x14e/0x17c [<000000000045e226>] mutex_lock_nested+0x42/0x3b4 [<00000000002c443e>] echo_char_raw+0x3a/0x9c [<00000000002c688c>] n_tty_receive_buf+0x1154/0x1208 [<00000000002ca0a2>] flush_to_ldisc+0x152/0x220 [<00000000002ca1da>] tty_flip_buffer_push+0x6a/0x90 [<00000000002cea74>] hvc_poll+0x244/0x2c8 [<00000000002ceb68>] khvcd+0x70/0x12c [<000000000015bbd0>] kthread+0x68/0xa0 [<0000000000109d5a>] kernel_thread_starter+0x6/0xc [<0000000000109d54>] kernel_thread_starter+0x0/0xc 1 lock held by khvcd/748: #0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> |
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| .. | ||
| agp | ||
| hw_random | ||
| ip2 | ||
| ipmi | ||
| mwave | ||
| pcmcia | ||
| rio | ||
| tpm | ||
| xilinx_hwicap | ||
| .gitignore | ||
| amiserial.c | ||
| apm-emulation.c | ||
| applicom.c | ||
| applicom.h | ||
| bfin-otp.c | ||
| briq_panel.c | ||
| bsr.c | ||
| cd1865.h | ||
| ChangeLog | ||
| consolemap.c | ||
| cp437.uni | ||
| cs5535_gpio.c | ||
| cyclades.c | ||
| defkeymap.c_shipped | ||
| defkeymap.map | ||
| digi1.h | ||
| digiFep1.h | ||
| digiPCI.h | ||
| ds1302.c | ||
| ds1620.c | ||
| dsp56k.c | ||
| dtlk.c | ||
| efirtc.c | ||
| epca.c | ||
| epca.h | ||
| epcaconfig.h | ||
| esp.c | ||
| generic_nvram.c | ||
| generic_serial.c | ||
| genrtc.c | ||
| hangcheck-timer.c | ||
| hpet.c | ||
| hvc_beat.c | ||
| hvc_console.c | ||
| hvc_console.h | ||
| hvc_irq.c | ||
| hvc_iseries.c | ||
| hvc_iucv.c | ||
| hvc_rtas.c | ||
| hvc_udbg.c | ||
| hvc_vio.c | ||
| hvc_xen.c | ||
| hvcs.c | ||
| hvsi.c | ||
| i8k.c | ||
| isicom.c | ||
| istallion.c | ||
| Kconfig | ||
| keyboard.c | ||
| lp.c | ||
| Makefile | ||
| mbcs.c | ||
| mbcs.h | ||
| mem.c | ||
| misc.c | ||
| mmtimer.c | ||
| moxa.c | ||
| moxa.h | ||
| mspec.c | ||
| mxser.c | ||
| mxser.h | ||
| n_hdlc.c | ||
| n_r3964.c | ||
| n_tty.c | ||
| nozomi.c | ||
| nsc_gpio.c | ||
| nvram.c | ||
| nwbutton.c | ||
| nwbutton.h | ||
| nwflash.c | ||
| pc8736x_gpio.c | ||
| ppdev.c | ||
| ps3flash.c | ||
| pty.c | ||
| random.c | ||
| raw.c | ||
| riscom8_reg.h | ||
| riscom8.c | ||
| riscom8.h | ||
| rocket_int.h | ||
| rocket.c | ||
| rocket.h | ||
| rtc.c | ||
| scc.h | ||
| scx200_gpio.c | ||
| selection.c | ||
| ser_a2232.c | ||
| ser_a2232.h | ||
| ser_a2232fw.ax | ||
| ser_a2232fw.h | ||
| serial167.c | ||
| snsc_event.c | ||
| snsc.c | ||
| snsc.h | ||
| sonypi.c | ||
| specialix_io8.h | ||
| specialix.c | ||
| stallion.c | ||
| sx.c | ||
| sx.h | ||
| sxboards.h | ||
| sxwindow.h | ||
| synclink_gt.c | ||
| synclink.c | ||
| synclinkmp.c | ||
| sysrq.c | ||
| tb0219.c | ||
| tlclk.c | ||
| toshiba.c | ||
| tty_audit.c | ||
| tty_buffer.c | ||
| tty_io.c | ||
| tty_ioctl.c | ||
| tty_ldisc.c | ||
| tty_port.c | ||
| vc_screen.c | ||
| viotape.c | ||
| virtio_console.c | ||
| vme_scc.c | ||
| vr41xx_giu.c | ||
| vt_ioctl.c | ||
| vt.c | ||