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40f70c03e3
Symptom: When entering the suspend with Android logcat running, printk() call gets stuck and never returns. The issue can be observed at printk()s on nonboot CPUs when going to offline with their interrupts disabled, and never seen at boot CPU (core0 in our case). Details: serial_console_write() lacks of appropriate spinlock handling. In SMP systems, as long as sci_transmit_chars() is being processed at one CPU core, serial_console_write() can stuck at the other CPU core(s), when it tries to access to the same serial port _without_ a proper locking. serial_console_write() waits for the transmit FIFO getting empty, while sci_transmit_chars() writes data to the FIFO. In general, peripheral interrupts are routed to boot CPU (core0) by Linux ARM standard affinity settings. SCI(F) interrupts are handled by core0, so sci_transmit_chars() is processed on core0 as well. When logcat is running, it writes enormous log data to the kernel at every moment, forever. So core0 can repeatedly continue to process sci_transmit_chars() in its interrupt handler, which eventually makes the other CPU core(s) stuck at serial_console_write(). Looking at serial/8250.c, this is a known console write lockup issue with SMP kernels. Fix the sh-sci driver in the same way 8250.c does. Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| hvc | ||
| ipwireless | ||
| serial | ||
| vt | ||
| amiserial.c | ||
| bfin_jtag_comm.c | ||
| cyclades.c | ||
| ehv_bytechan.c | ||
| isicom.c | ||
| Kconfig | ||
| Makefile | ||
| moxa.c | ||
| moxa.h | ||
| mxser.c | ||
| mxser.h | ||
| n_gsm.c | ||
| n_hdlc.c | ||
| n_r3964.c | ||
| n_tracerouter.c | ||
| n_tracesink.c | ||
| n_tracesink.h | ||
| n_tty.c | ||
| nozomi.c | ||
| pty.c | ||
| rocket_int.h | ||
| rocket.c | ||
| rocket.h | ||
| synclink_gt.c | ||
| synclink.c | ||
| synclinkmp.c | ||
| sysrq.c | ||
| tty_audit.c | ||
| tty_buffer.c | ||
| tty_io.c | ||
| tty_ioctl.c | ||
| tty_ldisc.c | ||
| tty_mutex.c | ||
| tty_port.c | ||