linux-stable.git/drivers/tty/serial, branch v4.19.26 Linux kernel stable tree serial: sh-sci: Do not free irqs that have already been freed 2019-02-12T18:47:26+00:00 Chris Brandt chris.brandt@renesas.com 2019-01-28T18:25:56+00:00 c287265bfa65deff9f3af30f048efa87030bb425 commit 4d95987a32db53f3beca76f8c4c8309ef6a5f192 upstream. Since IRQs might be muxed on some parts, we need to pay attention when we are freeing them. Otherwise we get the ugly WARNING "Trying to free already-free IRQ 20". Fixes: 628c534ae735 ("serial: sh-sci: Improve support for separate TEI and DRI interrupts") Cc: stable <stable@vger.kernel.org> Signed-off-by: Chris Brandt <chris.brandt@renesas.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4d95987a32db53f3beca76f8c4c8309ef6a5f192 upstream.

Since IRQs might be muxed on some parts, we need to pay attention when we
are freeing them.
Otherwise we get the ugly WARNING "Trying to free already-free IRQ 20".

Fixes: 628c534ae735 ("serial: sh-sci: Improve support for separate TEI and DRI interrupts")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: Make PCI class test non fatal 2019-02-12T18:47:26+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-01-24T21:51:21+00:00 57a3ef4dd520e089858484cd68a71c1858600436 commit 824d17c57b0abbcb9128fb3f7327fae14761914b upstream. As has been reported the National Instruments serial cards have broken PCI class. The commit 7d8905d06405 ("serial: 8250_pci: Enable device after we check black list") made the PCI class check mandatory for the case when device is listed in a quirk list. Make PCI class test non fatal to allow broken card be enumerated. Fixes: 7d8905d06405 ("serial: 8250_pci: Enable device after we check black list") Cc: stable <stable@vger.kernel.org> Reported-by: Guan Yung Tseng <guan.yung.tseng@ni.com> Tested-by: Guan Yung Tseng <guan.yung.tseng@ni.com> Tested-by: KHUENY.Gerhard <Gerhard.KHUENY@bachmann.info> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 824d17c57b0abbcb9128fb3f7327fae14761914b upstream.

As has been reported the National Instruments serial cards have broken
PCI class.

The commit 7d8905d06405

  ("serial: 8250_pci: Enable device after we check black list")

made the PCI class check mandatory for the case when device is listed in
a quirk list.

Make PCI class test non fatal to allow broken card be enumerated.

Fixes: 7d8905d06405 ("serial: 8250_pci: Enable device after we check black list")
Cc: stable <stable@vger.kernel.org>
Reported-by: Guan Yung Tseng <guan.yung.tseng@ni.com>
Tested-by: Guan Yung Tseng <guan.yung.tseng@ni.com>
Tested-by: KHUENY.Gerhard <Gerhard.KHUENY@bachmann.info>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: fix race between flush_to_ldisc and tty_open 2019-02-12T18:47:26+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2019-01-31T09:43:16+00:00 f50a8b34d7e4bbb3331f11de1b65adb563e4eb69 commit fedb5760648a291e949f2380d383b5b2d2749b5e upstream. There still is a race window after the commit b027e2298bd588 ("tty: fix data race between tty_init_dev and flush of buf"), and we encountered this crash issue if receive_buf call comes before tty initialization completes in tty_open and tty->driver_data may be NULL. CPU0 CPU1 ---- ---- tty_open tty_init_dev tty_ldisc_unlock schedule flush_to_ldisc receive_buf tty_port_default_receive_buf tty_ldisc_receive_buf n_tty_receive_buf_common __receive_buf uart_flush_chars uart_start /*tty->driver_data is NULL*/ tty->ops->open /*init tty->driver_data*/ it can be fixed by extending ldisc semaphore lock in tty_init_dev to driver_data initialized completely after tty->ops->open(), but this will lead to get lock on one function and unlock in some other function, and hard to maintain, so fix this race only by checking tty->driver_data when receiving, and return if tty->driver_data is NULL, and n_tty_receive_buf_common maybe calls uart_unthrottle, so add the same check. Because the tty layer knows nothing about the driver associated with the device, the tty layer can not do anything here, it is up to the tty driver itself to check for this type of race. Fix up the serial driver to correctly check to see if it is finished binding with the device when being called, and if not, abort the tty calls. [Description and problem report and testing from Li RongQing, I rewrote the patch to be in the serial layer, not in the tty core - gregkh] Reported-by: Li RongQing <lirongqing@baidu.com> Tested-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: Wang Li <wangli39@baidu.com> Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fedb5760648a291e949f2380d383b5b2d2749b5e upstream.

There still is a race window after the commit b027e2298bd588
("tty: fix data race between tty_init_dev and flush of buf"),
and we encountered this crash issue if receive_buf call comes
before tty initialization completes in tty_open and
tty->driver_data may be NULL.

CPU0                                    CPU1
----                                    ----
                                  tty_open
                                   tty_init_dev
                                     tty_ldisc_unlock
                                       schedule
flush_to_ldisc
 receive_buf
  tty_port_default_receive_buf
   tty_ldisc_receive_buf
    n_tty_receive_buf_common
      __receive_buf
       uart_flush_chars
        uart_start
        /*tty->driver_data is NULL*/
                                   tty->ops->open
                                   /*init tty->driver_data*/

it can be fixed by extending ldisc semaphore lock in tty_init_dev
to driver_data initialized completely after tty->ops->open(), but
this will lead to get lock on one function and unlock in some other
function, and hard to maintain, so fix this race only by checking
tty->driver_data when receiving, and return if tty->driver_data
is NULL, and n_tty_receive_buf_common maybe calls uart_unthrottle,
so add the same check.

Because the tty layer knows nothing about the driver associated with the
device, the tty layer can not do anything here, it is up to the tty
driver itself to check for this type of race.  Fix up the serial driver
to correctly check to see if it is finished binding with the device when
being called, and if not, abort the tty calls.

[Description and problem report and testing from Li RongQing, I rewrote
the patch to be in the serial layer, not in the tty core - gregkh]

Reported-by: Li RongQing <lirongqing@baidu.com>
Tested-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Wang Li <wangli39@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: samsung: Properly set flags in autoCTS mode 2019-02-12T18:47:11+00:00 Beomho Seo beomho.seo@samsung.com 2018-12-14T11:34:08+00:00 283d0464734e3366b16d03efa423ce5c596fe295 [ Upstream commit 31e933645742ee6719d37573a27cce0761dcf92b ] Commit 391f93f2ec9f ("serial: core: Rework hw-assited flow control support") has changed the way the autoCTS mode is handled. According to that change, serial drivers which enable H/W autoCTS mode must set UPSTAT_AUTOCTS to prevent the serial core from inadvertently disabling TX. This patch adds proper handling of UPSTAT_AUTOCTS flag. Signed-off-by: Beomho Seo <beomho.seo@samsung.com> [mszyprow: rephrased commit message] Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 31e933645742ee6719d37573a27cce0761dcf92b ]

Commit 391f93f2ec9f ("serial: core: Rework hw-assited flow control support")
has changed the way the autoCTS mode is handled.

According to that change, serial drivers which enable H/W autoCTS mode must
set UPSTAT_AUTOCTS to prevent the serial core from inadvertently disabling
TX. This patch adds proper handling of UPSTAT_AUTOCTS flag.

Signed-off-by: Beomho Seo <beomho.seo@samsung.com>
[mszyprow: rephrased commit message]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: sh-sci: Resume PIO in sci_rx_interrupt() on DMA failure 2019-02-12T18:47:11+00:00 Geert Uytterhoeven geert+renesas@glider.be 2018-12-13T18:44:43+00:00 193de98205980e87f545fa94fc244c2c93ef132e [ Upstream commit 71ab1c0336c71ace5725740f200beca9667a339f ] On (H)SCIF, sci_submit_rx() is called in the receive interrupt handler. Hence if DMA submission fails, the interrupt handler should resume handling reception using PIO, else no more data is received. Make sci_submit_rx() return an error indicator, so the receive interrupt handler can act appropriately. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 71ab1c0336c71ace5725740f200beca9667a339f ]

On (H)SCIF, sci_submit_rx() is called in the receive interrupt handler.
Hence if DMA submission fails, the interrupt handler should resume
handling reception using PIO, else no more data is received.

Make sci_submit_rx() return an error indicator, so the receive interrupt
handler can act appropriately.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: sh-sci: Fix locking in sci_submit_rx() 2019-02-12T18:47:11+00:00 Geert Uytterhoeven geert+renesas@glider.be 2018-12-13T18:44:41+00:00 d71126505dba982e4309370efa4bd804f8693f36 [ Upstream commit dd1f2250da95e87cb3e612858f94b14f99445a7c ] Some callers of sci_submit_rx() hold the port spinlock, others don't. During fallback to PIO, the driver needs to obtain the port spinlock. If the lock was already held, spinlock recursion is detected, causing a deadlock: BUG: spinlock recursion on CPU#0. Fix this by adding a flag parameter to sci_submit_rx() for the caller to indicate the port spinlock is already held, so spinlock recursion can be avoided. Move the spin_lock_irqsave() up, so all DMA disable steps are protected, which is safe as the recently introduced dmaengine_terminate_async() can be called in atomic context. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit dd1f2250da95e87cb3e612858f94b14f99445a7c ]

Some callers of sci_submit_rx() hold the port spinlock, others don't.
During fallback to PIO, the driver needs to obtain the port spinlock.
If the lock was already held, spinlock recursion is detected, causing a
deadlock: BUG: spinlock recursion on CPU#0.

Fix this by adding a flag parameter to sci_submit_rx() for the caller to
indicate the port spinlock is already held, so spinlock recursion can be
avoided.

Move the spin_lock_irqsave() up, so all DMA disable steps are protected,
which is safe as the recently introduced dmaengine_terminate_async() can
be called in atomic context.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: fsl_lpuart: clear parity enable bit when disable parity 2019-02-12T18:46:59+00:00 Andy Duan fugang.duan@nxp.com 2018-10-16T07:32:22+00:00 49796c356187d888bc9b596c9ad138d9f8d3fa36 [ Upstream commit 397bd9211fe014b347ca8f95a8f4e1017bac1aeb ] Current driver only enable parity enable bit and never clear it when user set the termios. The fix clear the parity enable bit when PARENB flag is not set in termios->c_cflag. Cc: Lukas Wunner <lukas@wunner.de> Signed-off-by: Andy Duan <fugang.duan@nxp.com> Reviewed-by: Fabio Estevam <festevam@gmail.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 397bd9211fe014b347ca8f95a8f4e1017bac1aeb ]

Current driver only enable parity enable bit and never clear it
when user set the termios. The fix clear the parity enable bit when
PARENB flag is not set in termios->c_cflag.

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Andy Duan <fugang.duan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
uart: Fix crash in uart_write and uart_put_char 2019-01-31T07:14:36+00:00 Samir Virmani samir@embedur.com 2019-01-16T18:28:07+00:00 6d15ef2c912ab0ba3602322ea3227467212a4ca0 commit aff9cf5955185d1f183227e46c5f8673fa483813 upstream. We were experiencing a crash similar to the one reported as part of commit:a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()") in our testbed as well. We continue to observe the same crash after integrating the commit a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()") On reviewing the change, the port lock should be taken prior to checking for if (!circ->buf) in fn. __uart_put_char and other fns. that update the buffer uart_state->xmit. Traceback: [11/27/2018 06:24:32.4870] Unable to handle kernel NULL pointer dereference at virtual address 0000003b [11/27/2018 06:24:32.4950] PC is at memcpy+0x48/0x180 [11/27/2018 06:24:32.4950] LR is at uart_write+0x74/0x120 [11/27/2018 06:24:32.4950] pc : [<ffffffc0002e6808>] lr : [<ffffffc0003747cc>] pstate: 000001c5 [11/27/2018 06:24:32.4950] sp : ffffffc076433d30 [11/27/2018 06:24:32.4950] x29: ffffffc076433d30 x28: 0000000000000140 [11/27/2018 06:24:32.4950] x27: ffffffc0009b9d5e x26: ffffffc07ce36580 [11/27/2018 06:24:32.4950] x25: 0000000000000000 x24: 0000000000000140 [11/27/2018 06:24:32.4950] x23: ffffffc000891200 x22: ffffffc01fc34000 [11/27/2018 06:24:32.4950] x21: 0000000000000fff x20: 0000000000000076 [11/27/2018 06:24:32.4950] x19: 0000000000000076 x18: 0000000000000000 [11/27/2018 06:24:32.4950] x17: 000000000047cf08 x16: ffffffc000099e68 [11/27/2018 06:24:32.4950] x15: 0000000000000018 x14: 776d726966205948 [11/27/2018 06:24:32.4950] x13: 50203a6c6974755f x12: 74647075205d3333 [11/27/2018 06:24:32.4950] x11: 3a35323a36203831 x10: 30322f37322f3131 [11/27/2018 06:24:32.4950] x9 : 5b205d303638342e x8 : 746164206f742070 [11/27/2018 06:24:32.4950] x7 : 7520736920657261 x6 : 000000000000003b [11/27/2018 06:24:32.4950] x5 : 000000000000817a x4 : 0000000000000008 [11/27/2018 06:24:32.4950] x3 : 2f37322f31312a5b x2 : 000000000000006e [11/27/2018 06:24:32.4950] x1 : ffffffc0009b9cf0 x0 : 000000000000003b [11/27/2018 06:24:32.4950] CPU2: stopping [11/27/2018 06:24:32.4950] CPU: 2 PID: 0 Comm: swapper/2 Tainted: P D O 4.1.51 #3 [11/27/2018 06:24:32.4950] Hardware name: Broadcom-v8A (DT) [11/27/2018 06:24:32.4950] Call trace: [11/27/2018 06:24:32.4950] [<ffffffc0000883b8>] dump_backtrace+0x0/0x150 [11/27/2018 06:24:32.4950] [<ffffffc00008851c>] show_stack+0x14/0x20 [11/27/2018 06:24:32.4950] [<ffffffc0005ee810>] dump_stack+0x90/0xb0 [11/27/2018 06:24:32.4950] [<ffffffc00008e844>] handle_IPI+0x18c/0x1a0 [11/27/2018 06:24:32.4950] [<ffffffc000080c68>] gic_handle_irq+0x88/0x90 Fixes: a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()") Cc: stable <stable@vger.kernel.org> Signed-off-by: Samir Virmani <samir@embedur.com> Acked-by: Tycho Andersen <tycho@tycho.ws> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit aff9cf5955185d1f183227e46c5f8673fa483813 upstream.

We were experiencing a crash similar to the one reported as part of
commit:a5ba1d95e46e ("uart: fix race between uart_put_char() and
uart_shutdown()") in our testbed as well. We continue to observe the same
crash after integrating the commit a5ba1d95e46e ("uart: fix race between
uart_put_char() and uart_shutdown()")

On reviewing the change, the port lock should be taken prior to checking for
if (!circ->buf) in fn. __uart_put_char and other fns. that update the buffer
uart_state->xmit.

Traceback:

[11/27/2018 06:24:32.4870] Unable to handle kernel NULL pointer dereference
                           at virtual address 0000003b

[11/27/2018 06:24:32.4950] PC is at memcpy+0x48/0x180
[11/27/2018 06:24:32.4950] LR is at uart_write+0x74/0x120
[11/27/2018 06:24:32.4950] pc : [<ffffffc0002e6808>]
                           lr : [<ffffffc0003747cc>] pstate: 000001c5
[11/27/2018 06:24:32.4950] sp : ffffffc076433d30
[11/27/2018 06:24:32.4950] x29: ffffffc076433d30 x28: 0000000000000140
[11/27/2018 06:24:32.4950] x27: ffffffc0009b9d5e x26: ffffffc07ce36580
[11/27/2018 06:24:32.4950] x25: 0000000000000000 x24: 0000000000000140
[11/27/2018 06:24:32.4950] x23: ffffffc000891200 x22: ffffffc01fc34000
[11/27/2018 06:24:32.4950] x21: 0000000000000fff x20: 0000000000000076
[11/27/2018 06:24:32.4950] x19: 0000000000000076 x18: 0000000000000000
[11/27/2018 06:24:32.4950] x17: 000000000047cf08 x16: ffffffc000099e68
[11/27/2018 06:24:32.4950] x15: 0000000000000018 x14: 776d726966205948
[11/27/2018 06:24:32.4950] x13: 50203a6c6974755f x12: 74647075205d3333
[11/27/2018 06:24:32.4950] x11: 3a35323a36203831 x10: 30322f37322f3131
[11/27/2018 06:24:32.4950] x9 : 5b205d303638342e x8 : 746164206f742070
[11/27/2018 06:24:32.4950] x7 : 7520736920657261 x6 : 000000000000003b
[11/27/2018 06:24:32.4950] x5 : 000000000000817a x4 : 0000000000000008
[11/27/2018 06:24:32.4950] x3 : 2f37322f31312a5b x2 : 000000000000006e
[11/27/2018 06:24:32.4950] x1 : ffffffc0009b9cf0 x0 : 000000000000003b

[11/27/2018 06:24:32.4950] CPU2: stopping
[11/27/2018 06:24:32.4950] CPU: 2 PID: 0 Comm: swapper/2 Tainted: P      D    O    4.1.51 #3
[11/27/2018 06:24:32.4950] Hardware name: Broadcom-v8A (DT)
[11/27/2018 06:24:32.4950] Call trace:
[11/27/2018 06:24:32.4950] [<ffffffc0000883b8>] dump_backtrace+0x0/0x150
[11/27/2018 06:24:32.4950] [<ffffffc00008851c>] show_stack+0x14/0x20
[11/27/2018 06:24:32.4950] [<ffffffc0005ee810>] dump_stack+0x90/0xb0
[11/27/2018 06:24:32.4950] [<ffffffc00008e844>] handle_IPI+0x18c/0x1a0
[11/27/2018 06:24:32.4950] [<ffffffc000080c68>] gic_handle_irq+0x88/0x90

Fixes: a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Samir Virmani <samir@embedur.com>
Acked-by: Tycho Andersen <tycho@tycho.ws>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty/serial: do not free trasnmit buffer page under port lock 2019-01-26T08:32:40+00:00 Sergey Senozhatsky sergey.senozhatsky.work@gmail.com 2018-12-13T04:58:39+00:00 f74fc96e32ab43bfcb91eeb8f144e4fb16b6d6d0 [ Upstream commit d72402145ace0697a6a9e8e75a3de5bf3375f78d ] LKP has hit yet another circular locking dependency between uart console drivers and debugobjects [1]: CPU0 CPU1 rhltable_init() __init_work() debug_object_init uart_shutdown() /* db->lock */ /* uart_port->lock */ debug_print_object() free_page() printk() call_console_drivers() debug_check_no_obj_freed() /* uart_port->lock */ /* db->lock */ debug_print_object() So there are two dependency chains: uart_port->lock -> db->lock And db->lock -> uart_port->lock This particular circular locking dependency can be addressed in several ways: a) One way would be to move debug_print_object() out of db->lock scope and, thus, break the db->lock -> uart_port->lock chain. b) Another one would be to free() transmit buffer page out of db->lock in UART code; which is what this patch does. It makes sense to apply a) and b) independently: there are too many things going on behind free(), none of which depend on uart_port->lock. The patch fixes transmit buffer page free() in uart_shutdown() and, additionally, in uart_port_startup() (as was suggested by Dmitry Safonov). [1] https://lore.kernel.org/lkml/20181211091154.GL23332@shao2-debian/T/#u Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Waiman Long <longman@redhat.com> Cc: Dmitry Safonov <dima@arista.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d72402145ace0697a6a9e8e75a3de5bf3375f78d ]

LKP has hit yet another circular locking dependency between uart
console drivers and debugobjects [1]:

     CPU0                                    CPU1

                                            rhltable_init()
                                             __init_work()
                                              debug_object_init
     uart_shutdown()                          /* db->lock */
      /* uart_port->lock */                    debug_print_object()
       free_page()                              printk()
                                                 call_console_drivers()
        debug_check_no_obj_freed()                /* uart_port->lock */
         /* db->lock */
          debug_print_object()

So there are two dependency chains:
	uart_port->lock -> db->lock
And
	db->lock -> uart_port->lock

This particular circular locking dependency can be addressed in several
ways:

a) One way would be to move debug_print_object() out of db->lock scope
   and, thus, break the db->lock -> uart_port->lock chain.
b) Another one would be to free() transmit buffer page out of db->lock
   in UART code; which is what this patch does.

It makes sense to apply a) and b) independently: there are too many things
going on behind free(), none of which depend on uart_port->lock.

The patch fixes transmit buffer page free() in uart_shutdown() and,
additionally, in uart_port_startup() (as was suggested by Dmitry Safonov).

[1] https://lore.kernel.org/lkml/20181211091154.GL23332@shao2-debian/T/#u
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Dmitry Safonov <dima@arista.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: set suppress_bind_attrs flag only if builtin 2019-01-26T08:32:34+00:00 Anders Roxell anders.roxell@linaro.org 2018-10-30T11:35:44+00:00 4c7c36a7f3487a6ee3a178022081165ce369c0a5 [ Upstream commit 646097940ad35aa2c1f2012af932d55976a9f255 ] When the test 'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, arch_initcall(pl011_init) came before subsys_initcall(default_bdi_init). devtmpfs gets killed because we try to remove a file and decrement the wb reference count before the noop_backing_device_info gets initialized. [ 0.332075] Serial: AMBA PL011 UART driver [ 0.485276] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 39, base_baud = 0) is a PL011 rev1 [ 0.502382] console [ttyAMA0] enabled [ 0.515710] Unable to handle kernel paging request at virtual address 0000800074c12000 [ 0.516053] Mem abort info: [ 0.516222] ESR = 0x96000004 [ 0.516417] Exception class = DABT (current EL), IL = 32 bits [ 0.516641] SET = 0, FnV = 0 [ 0.516826] EA = 0, S1PTW = 0 [ 0.516984] Data abort info: [ 0.517149] ISV = 0, ISS = 0x00000004 [ 0.517339] CM = 0, WnR = 0 [ 0.517553] [0000800074c12000] user address but active_mm is swapper [ 0.517928] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 0.518305] Modules linked in: [ 0.518839] CPU: 0 PID: 13 Comm: kdevtmpfs Not tainted 4.19.0-rc5-next-20180928-00002-g2ba39ab0cd01-dirty #82 [ 0.519307] Hardware name: linux,dummy-virt (DT) [ 0.519681] pstate: 80000005 (Nzcv daif -PAN -UAO) [ 0.519959] pc : __destroy_inode+0x94/0x2a8 [ 0.520212] lr : __destroy_inode+0x78/0x2a8 [ 0.520401] sp : ffff0000098c3b20 [ 0.520590] x29: ffff0000098c3b20 x28: 00000000087a3714 [ 0.520904] x27: 0000000000002000 x26: 0000000000002000 [ 0.521179] x25: ffff000009583000 x24: 0000000000000000 [ 0.521467] x23: ffff80007bb52000 x22: ffff80007bbaa7c0 [ 0.521737] x21: ffff0000093f9338 x20: 0000000000000000 [ 0.522033] x19: ffff80007bbb05d8 x18: 0000000000000400 [ 0.522376] x17: 0000000000000000 x16: 0000000000000000 [ 0.522727] x15: 0000000000000400 x14: 0000000000000400 [ 0.523068] x13: 0000000000000001 x12: 0000000000000001 [ 0.523421] x11: 0000000000000000 x10: 0000000000000970 [ 0.523749] x9 : ffff0000098c3a60 x8 : ffff80007bbab190 [ 0.524017] x7 : ffff80007bbaa880 x6 : 0000000000000c88 [ 0.524305] x5 : ffff0000093d96c8 x4 : 61c8864680b583eb [ 0.524567] x3 : ffff0000093d6180 x2 : ffffffffffffffff [ 0.524872] x1 : 0000800074c12000 x0 : 0000800074c12000 [ 0.525207] Process kdevtmpfs (pid: 13, stack limit = 0x(____ptrval____)) [ 0.525529] Call trace: [ 0.525806] __destroy_inode+0x94/0x2a8 [ 0.526108] destroy_inode+0x34/0x88 [ 0.526370] evict+0x144/0x1c8 [ 0.526636] iput+0x184/0x230 [ 0.526871] dentry_unlink_inode+0x118/0x130 [ 0.527152] d_delete+0xd8/0xe0 [ 0.527420] vfs_unlink+0x240/0x270 [ 0.527665] handle_remove+0x1d8/0x330 [ 0.527875] devtmpfsd+0x138/0x1c8 [ 0.528085] kthread+0x14c/0x158 [ 0.528291] ret_from_fork+0x10/0x18 [ 0.528720] Code: 92800002 aa1403e0 d538d081 8b010000 (c85f7c04) [ 0.529367] ---[ end trace 5a3dee47727f877c ]--- Rework to set suppress_bind_attrs flag to avoid removing the device when CONFIG_DEBUG_TEST_DRIVER_REMOVE=y. This applies for pic32_uart and xilinx_uartps as well. Co-developed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 646097940ad35aa2c1f2012af932d55976a9f255 ]

When the test 'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled,
arch_initcall(pl011_init) came before subsys_initcall(default_bdi_init).
devtmpfs gets killed because we try to remove a file and decrement the
wb reference count before the noop_backing_device_info gets initialized.

[    0.332075] Serial: AMBA PL011 UART driver
[    0.485276] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 39, base_baud = 0) is a PL011 rev1
[    0.502382] console [ttyAMA0] enabled
[    0.515710] Unable to handle kernel paging request at virtual address 0000800074c12000
[    0.516053] Mem abort info:
[    0.516222]   ESR = 0x96000004
[    0.516417]   Exception class = DABT (current EL), IL = 32 bits
[    0.516641]   SET = 0, FnV = 0
[    0.516826]   EA = 0, S1PTW = 0
[    0.516984] Data abort info:
[    0.517149]   ISV = 0, ISS = 0x00000004
[    0.517339]   CM = 0, WnR = 0
[    0.517553] [0000800074c12000] user address but active_mm is swapper
[    0.517928] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[    0.518305] Modules linked in:
[    0.518839] CPU: 0 PID: 13 Comm: kdevtmpfs Not tainted 4.19.0-rc5-next-20180928-00002-g2ba39ab0cd01-dirty #82
[    0.519307] Hardware name: linux,dummy-virt (DT)
[    0.519681] pstate: 80000005 (Nzcv daif -PAN -UAO)
[    0.519959] pc : __destroy_inode+0x94/0x2a8
[    0.520212] lr : __destroy_inode+0x78/0x2a8
[    0.520401] sp : ffff0000098c3b20
[    0.520590] x29: ffff0000098c3b20 x28: 00000000087a3714
[    0.520904] x27: 0000000000002000 x26: 0000000000002000
[    0.521179] x25: ffff000009583000 x24: 0000000000000000
[    0.521467] x23: ffff80007bb52000 x22: ffff80007bbaa7c0
[    0.521737] x21: ffff0000093f9338 x20: 0000000000000000
[    0.522033] x19: ffff80007bbb05d8 x18: 0000000000000400
[    0.522376] x17: 0000000000000000 x16: 0000000000000000
[    0.522727] x15: 0000000000000400 x14: 0000000000000400
[    0.523068] x13: 0000000000000001 x12: 0000000000000001
[    0.523421] x11: 0000000000000000 x10: 0000000000000970
[    0.523749] x9 : ffff0000098c3a60 x8 : ffff80007bbab190
[    0.524017] x7 : ffff80007bbaa880 x6 : 0000000000000c88
[    0.524305] x5 : ffff0000093d96c8 x4 : 61c8864680b583eb
[    0.524567] x3 : ffff0000093d6180 x2 : ffffffffffffffff
[    0.524872] x1 : 0000800074c12000 x0 : 0000800074c12000
[    0.525207] Process kdevtmpfs (pid: 13, stack limit = 0x(____ptrval____))
[    0.525529] Call trace:
[    0.525806]  __destroy_inode+0x94/0x2a8
[    0.526108]  destroy_inode+0x34/0x88
[    0.526370]  evict+0x144/0x1c8
[    0.526636]  iput+0x184/0x230
[    0.526871]  dentry_unlink_inode+0x118/0x130
[    0.527152]  d_delete+0xd8/0xe0
[    0.527420]  vfs_unlink+0x240/0x270
[    0.527665]  handle_remove+0x1d8/0x330
[    0.527875]  devtmpfsd+0x138/0x1c8
[    0.528085]  kthread+0x14c/0x158
[    0.528291]  ret_from_fork+0x10/0x18
[    0.528720] Code: 92800002 aa1403e0 d538d081 8b010000 (c85f7c04)
[    0.529367] ---[ end trace 5a3dee47727f877c ]---

Rework to set suppress_bind_attrs flag to avoid removing the device when
CONFIG_DEBUG_TEST_DRIVER_REMOVE=y. This applies for pic32_uart and
xilinx_uartps as well.

Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>