linux-stable.git/drivers/tty/serial, branch linux-5.8.y Linux kernel stable tree serial: pl011: Fix lockdep splat when handling magic-sysrq interrupt 2020-11-01T11:45:42+00:00 Peter Zijlstra peterz@infradead.org 2020-09-30T12:04:32+00:00 53faca2f4ca3443aa00f7f46c4f327bf4a98728e commit 534cf755d9df99e214ddbe26b91cd4d81d2603e2 upstream. Issuing a magic-sysrq via the PL011 causes the following lockdep splat, which is easily reproducible under QEMU: | sysrq: Changing Loglevel | sysrq: Loglevel set to 9 | | ====================================================== | WARNING: possible circular locking dependency detected | 5.9.0-rc7 #1 Not tainted | ------------------------------------------------------ | systemd-journal/138 is trying to acquire lock: | ffffab133ad950c0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x34/0x70 | | but task is already holding lock: | ffff0001fd47b098 (&port_lock_key){-.-.}-{2:2}, at: pl011_int+0x40/0x488 | | which lock already depends on the new lock. [...] | Possible unsafe locking scenario: | | CPU0 CPU1 | ---- ---- | lock(&port_lock_key); | lock(console_owner); | lock(&port_lock_key); | lock(console_owner); | | *** DEADLOCK *** The issue being that CPU0 takes 'port_lock' on the irq path in pl011_int() before taking 'console_owner' on the printk() path, whereas CPU1 takes the two locks in the opposite order on the printk() path due to setting the "console_owner" prior to calling into into the actual console driver. Fix this in the same way as the msm-serial driver by dropping 'port_lock' before handling the sysrq. Cc: <stable@vger.kernel.org> # 4.19+ Cc: Russell King <linux@armlinux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20200811101313.GA6970@willie-the-truck Signed-off-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200930120432.16551-1-will@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 534cf755d9df99e214ddbe26b91cd4d81d2603e2 upstream.

Issuing a magic-sysrq via the PL011 causes the following lockdep splat,
which is easily reproducible under QEMU:

  | sysrq: Changing Loglevel
  | sysrq: Loglevel set to 9
  |
  | ======================================================
  | WARNING: possible circular locking dependency detected
  | 5.9.0-rc7 #1 Not tainted
  | ------------------------------------------------------
  | systemd-journal/138 is trying to acquire lock:
  | ffffab133ad950c0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x34/0x70
  |
  | but task is already holding lock:
  | ffff0001fd47b098 (&port_lock_key){-.-.}-{2:2}, at: pl011_int+0x40/0x488
  |
  | which lock already depends on the new lock.

  [...]

  |  Possible unsafe locking scenario:
  |
  |        CPU0                    CPU1
  |        ----                    ----
  |   lock(&port_lock_key);
  |                                lock(console_owner);
  |                                lock(&port_lock_key);
  |   lock(console_owner);
  |
  |  *** DEADLOCK ***

The issue being that CPU0 takes 'port_lock' on the irq path in pl011_int()
before taking 'console_owner' on the printk() path, whereas CPU1 takes
the two locks in the opposite order on the printk() path due to setting
the "console_owner" prior to calling into into the actual console driver.

Fix this in the same way as the msm-serial driver by dropping 'port_lock'
before handling the sysrq.

Cc: <stable@vger.kernel.org> # 4.19+
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20200811101313.GA6970@willie-the-truck
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200930120432.16551-1-will@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: qcom_geni_serial: To correct QUP Version detection logic 2020-11-01T11:45:42+00:00 Paras Sharma parashar@codeaurora.org 2020-09-30T06:05:26+00:00 e3f6c126a3f72b9dbe53bf3e96c27b4dc346e07c commit c9ca43d42ed8d5fd635d327a664ed1d8579eb2af upstream. For QUP IP versions 2.5 and above the oversampling rate is halved from 32 to 16. Commit ce734600545f ("tty: serial: qcom_geni_serial: Update the oversampling rate") is pushed to handle this scenario. But the existing logic is failing to classify QUP Version 3.0 into the correct group ( 2.5 and above). As result Serial Engine clocks are not configured properly for baud rate and garbage data is sampled to FIFOs from the line. So, fix the logic to detect QUP with versions 2.5 and above. Fixes: ce734600545f ("tty: serial: qcom_geni_serial: Update the oversampling rate") Cc: stable <stable@vger.kernel.org> Signed-off-by: Paras Sharma <parashar@codeaurora.org> Reviewed-by: Akash Asthana <akashast@codeaurora.org> Link: https://lore.kernel.org/r/1601445926-23673-1-git-send-email-parashar@codeaurora.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c9ca43d42ed8d5fd635d327a664ed1d8579eb2af upstream.

For QUP IP versions 2.5 and above the oversampling rate is
halved from 32 to 16.

Commit ce734600545f ("tty: serial: qcom_geni_serial: Update
the oversampling rate") is pushed to handle this scenario.
But the existing logic is failing to classify QUP Version 3.0
into the correct group ( 2.5 and above).

As result Serial Engine clocks are not configured properly for
baud rate and garbage data is sampled to FIFOs from the line.

So, fix the logic to detect QUP with versions 2.5 and above.

Fixes: ce734600545f ("tty: serial: qcom_geni_serial: Update the oversampling rate")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Paras Sharma <parashar@codeaurora.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Link: https://lore.kernel.org/r/1601445926-23673-1-git-send-email-parashar@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: fsl_lpuart: fix lpuart32_poll_get_char 2020-10-29T09:08:30+00:00 Peng Fan peng.fan@nxp.com 2020-09-29T09:55:09+00:00 3d53646d781b1f6008b637a78a9cd40e9ec86d1b commit 29788ab1d2bf26c130de8f44f9553ee78a27e8d5 upstream. The watermark is set to 1, so we need to input two chars to trigger RDRF using the original logic. With the new logic, we could always get the char when there is data in FIFO. Suggested-by: Fugang Duan <fugang.duan@nxp.com> Signed-off-by: Peng Fan <peng.fan@nxp.com> Link: https://lore.kernel.org/r/20200929095509.21680-1-peng.fan@nxp.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 29788ab1d2bf26c130de8f44f9553ee78a27e8d5 upstream.

The watermark is set to 1, so we need to input two chars to trigger RDRF
using the original logic. With the new logic, we could always get the
char when there is data in FIFO.

Suggested-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200929095509.21680-1-peng.fan@nxp.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: lpuart: fix lpuart32_write usage 2020-10-29T09:08:30+00:00 Peng Fan peng.fan@nxp.com 2020-09-29T09:19:20+00:00 40254b8d0f8b701edd20c14d9b1bb3cbede2d39b commit 9ea40db477c024dcb87321b7f32bd6ea12130ac2 upstream. The 2nd and 3rd parameter were wrongly used, and cause kernel abort when doing kgdb debug. Fixes: 1da17d7cf8e2 ("tty: serial: fsl_lpuart: Use appropriate lpuart32_* I/O funcs") Cc: stable <stable@vger.kernel.org> Signed-off-by: Peng Fan <peng.fan@nxp.com> Link: https://lore.kernel.org/r/20200929091920.22612-1-peng.fan@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9ea40db477c024dcb87321b7f32bd6ea12130ac2 upstream.

The 2nd and 3rd parameter were wrongly used, and cause kernel abort when
doing kgdb debug.

Fixes: 1da17d7cf8e2 ("tty: serial: fsl_lpuart: Use appropriate lpuart32_* I/O funcs")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200929091920.22612-1-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: earlycon dependency 2020-10-29T09:07:34+00:00 Tong Zhang ztong0001@gmail.com 2020-08-28T12:39:50+00:00 45f20b6066c3168e75e90d3a7bbc5b46e9ae025c [ Upstream commit 0fb9342d06b0f667b915ba58bfefc030e534a218 ] parse_options() in drivers/tty/serial/earlycon.c calls uart_parse_earlycon in drivers/tty/serial/serial_core.c therefore selecting SERIAL_EARLYCON should automatically select SERIAL_CORE, otherwise will result in symbol not found error during linking if SERIAL_CORE is not configured as builtin Fixes: 9aac5887595b ("tty/serial: add generic serial earlycon") Signed-off-by: Tong Zhang <ztong0001@gmail.com> Link: https://lore.kernel.org/r/20200828123949.2642-1-ztong0001@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0fb9342d06b0f667b915ba58bfefc030e534a218 ]

parse_options() in drivers/tty/serial/earlycon.c calls uart_parse_earlycon
in drivers/tty/serial/serial_core.c therefore selecting SERIAL_EARLYCON
should automatically select SERIAL_CORE, otherwise will result in symbol
not found error during linking if SERIAL_CORE is not configured as builtin

Fixes: 9aac5887595b ("tty/serial: add generic serial earlycon")
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20200828123949.2642-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: core: fix console port-lock regression 2020-09-23T11:00:01+00:00 Johan Hovold johan@kernel.org 2020-09-09T14:31:01+00:00 165b69c8f0738fe936fa085ef5e21adce84ed244 commit e0830dbf71f191851ed3772d2760f007b7c5bc3a upstream. Fix the port-lock initialisation regression introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by making sure that the lock is again initialised during console setup. The console may be registered before the serial controller has been probed in which case the port lock needs to be initialised during console setup by a call to uart_set_options(). The console-detach changes introduced a regression in several drivers by effectively removing that initialisation by not initialising the lock when the port is used as a console (which is always the case during console setup). Add back the early lock initialisation and instead use a new console-reinit flag to handle the case where a console is being re-attached through sysfs. The question whether the console-detach interface should have been added in the first place is left for another discussion. Note that the console-enabled check in uart_set_options() is not redundant because of kgdboc, which can end up reinitialising an already enabled console (see commit 42b6a1baa3ec ("serial_core: Don't re-initialize a previously initialized spinlock.")). Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable <stable@vger.kernel.org> # 5.7 Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200909143101.15389-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e0830dbf71f191851ed3772d2760f007b7c5bc3a upstream.

Fix the port-lock initialisation regression introduced by commit
a3cb39d258ef ("serial: core: Allow detach and attach serial device for
console") by making sure that the lock is again initialised during
console setup.

The console may be registered before the serial controller has been
probed in which case the port lock needs to be initialised during
console setup by a call to uart_set_options(). The console-detach
changes introduced a regression in several drivers by effectively
removing that initialisation by not initialising the lock when the port
is used as a console (which is always the case during console setup).

Add back the early lock initialisation and instead use a new
console-reinit flag to handle the case where a console is being
re-attached through sysfs.

The question whether the console-detach interface should have been added
in the first place is left for another discussion.

Note that the console-enabled check in uart_set_options() is not
redundant because of kgdboc, which can end up reinitialising an already
enabled console (see commit 42b6a1baa3ec ("serial_core: Don't
re-initialize a previously initialized spinlock.")).

Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>     # 5.7
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200909143101.15389-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: core: fix port-lock initialisation 2020-09-23T11:00:01+00:00 Johan Hovold johan@kernel.org 2020-09-09T14:31:00+00:00 8db58f3a6f169d9ecfa44ed741716ed1dd89534b commit fe88c6489264eaea23570dfdf03e1d3f5f47f423 upstream. Commit f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") tried to work around a breakage introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by adding a second initialisation of the port lock when registering the port. As reported by the build robots [1], this doesn't really solve the regression introduced by the console-detach changes and also adds a second redundant initialisation of the lock for normal ports. Start cleaning up this mess by removing the redundant initialisation and making sure that the port lock is again initialised once-only for ports that aren't already in use as a console. [1] https://lore.kernel.org/r/20200802054852.GR23458@shao2-debian Fixes: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable <stable@vger.kernel.org> # 5.7 Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fe88c6489264eaea23570dfdf03e1d3f5f47f423 upstream.

Commit f743061a85f5 ("serial: core: Initialise spin lock before use in
uart_configure_port()") tried to work around a breakage introduced by
commit a3cb39d258ef ("serial: core: Allow detach and attach serial
device for console") by adding a second initialisation of the port lock
when registering the port.

As reported by the build robots [1], this doesn't really solve the
regression introduced by the console-detach changes and also adds a
second redundant initialisation of the lock for normal ports.

Start cleaning up this mess by removing the redundant initialisation and
making sure that the port lock is again initialised once-only for ports
that aren't already in use as a console.

[1] https://lore.kernel.org/r/20200802054852.GR23458@shao2-debian

Fixes: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()")
Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>     # 5.7
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: Add Realtek 816a and 816b 2020-09-23T11:00:01+00:00 Tobias Diedrich tobiasdiedrich@gmail.com 2020-09-14T17:36:28+00:00 a406d438eba48c0e8e7c264edf40b2952a0d231c commit 3c5a87be170aba8ac40982182f812dcff6ed1ad1 upstream. These serial ports are exposed by the OOB-management-engine on RealManage-enabled network cards (e.g. AMD DASH enabled systems using Realtek cards). Because these have 3 BARs, they fail the "num_iomem <= 1" check in serial_pci_guess_board. I've manually checked the two IOMEM regions and BAR 2 doesn't seem to respond to reads, but BAR 4 seems to be an MMIO version of the IO ports (untested). With this change, the ports are detected: 0000:02:00.1: ttyS0 at I/O 0x2200 (irq = 82, base_baud = 115200) is a 16550A 0000:02:00.2: ttyS1 at I/O 0x2100 (irq = 55, base_baud = 115200) is a 16550A lspci output: 02:00.1 0700: 10ec:816a (rev 0e) (prog-if 02 [16550]) Subsystem: 17aa:5082 Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort+ <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin B routed to IRQ 82 IOMMU group: 11 Region 0: I/O ports at 2200 [size=256] Region 2: Memory at fd715000 (64-bit, non-prefetchable) [size=4K] Region 4: Memory at fd704000 (64-bit, non-prefetchable) [size=16K] Capabilities: [40] Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities: [70] Express (v2) Endpoint, MSI 01 DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s unlimited, L1 <64us ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq- RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop- MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr+ TransPend- LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s unlimited, L1 <64us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s (ok), Width x1 (ok) TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+ 10BitTagComp- 10BitTagReq- OBFF Via message/WAKE#, ExtFmt- EETLPPrefix- EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit- FRS- TPHComp- ExtTPHComp- AtomicOpsCap: 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- OBFF Disabled, AtomicOpsCtl: ReqEn- LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete- EqualizationPhase1- EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest- Retimer- 2Retimers- CrosslinkRes: unsupported Capabilities: [b0] MSI-X: Enable- Count=4 Masked- Vector table: BAR=4 offset=00000000 PBA: BAR=4 offset=00000800 Capabilities: [d0] Vital Product Data Not readable Capabilities: [100 v2] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+ CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn- MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 Capabilities: [160 v1] Device Serial Number 00-00-00-00-00-00-00-00 Capabilities: [170 v1] Latency Tolerance Reporting Max snoop latency: 0ns Max no snoop latency: 0ns Capabilities: [178 v1] L1 PM Substates L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+ PortCommonModeRestoreTime=150us PortTPowerOnTime=150us L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1- T_CommonMode=0us LTR1.2_Threshold=0ns L1SubCtl2: T_PwrOn=10us 02:00.2 0700: 10ec:816b (rev 0e) [...same...] Signed-off-by: Tobias Diedrich <tobiasdiedrich@gmail.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200914173628.GA22508@yamamaya.is-a-geek.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3c5a87be170aba8ac40982182f812dcff6ed1ad1 upstream.

These serial ports are exposed by the OOB-management-engine on
RealManage-enabled network cards (e.g. AMD DASH enabled systems using
Realtek cards).

Because these have 3 BARs, they fail the "num_iomem <= 1" check in
serial_pci_guess_board.

I've manually checked the two IOMEM regions and BAR 2 doesn't seem to
respond to reads, but BAR 4 seems to be an MMIO version of the IO ports
(untested).

With this change, the ports are detected:
0000:02:00.1: ttyS0 at I/O 0x2200 (irq = 82, base_baud = 115200) is a 16550A
0000:02:00.2: ttyS1 at I/O 0x2100 (irq = 55, base_baud = 115200) is a 16550A

lspci output:
02:00.1 0700: 10ec:816a (rev 0e) (prog-if 02 [16550])
        Subsystem: 17aa:5082
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort+ <TAbort- <MAbort- >SERR- <PERR- INTx-
        Interrupt: pin B routed to IRQ 82
        IOMMU group: 11
        Region 0: I/O ports at 2200 [size=256]
        Region 2: Memory at fd715000 (64-bit, non-prefetchable) [size=4K]
        Region 4: Memory at fd704000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [40] Power Management version 3
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
                Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+
                Address: 0000000000000000  Data: 0000
        Capabilities: [70] Express (v2) Endpoint, MSI 01
                DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s unlimited, L1 <64us
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W
                DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
                        MaxPayload 128 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr+ TransPend-
                LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s unlimited, L1 <64us
                        ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 2.5GT/s (ok), Width x1 (ok)
                        TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
                DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+
                         10BitTagComp- 10BitTagReq- OBFF Via message/WAKE#, ExtFmt- EETLPPrefix-
                         EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
                         FRS- TPHComp- ExtTPHComp-
                         AtomicOpsCap: 32bit- 64bit- 128bitCAS-
                DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- OBFF Disabled,
                         AtomicOpsCtl: ReqEn-
                LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete- EqualizationPhase1-
                         EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest-
                         Retimer- 2Retimers- CrosslinkRes: unsupported
        Capabilities: [b0] MSI-X: Enable- Count=4 Masked-
                Vector table: BAR=4 offset=00000000
                PBA: BAR=4 offset=00000800
        Capabilities: [d0] Vital Product Data
                Not readable
        Capabilities: [100 v2] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
                        MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
                HeaderLog: 00000000 00000000 00000000 00000000
        Capabilities: [160 v1] Device Serial Number 00-00-00-00-00-00-00-00
        Capabilities: [170 v1] Latency Tolerance Reporting
                Max snoop latency: 0ns
                Max no snoop latency: 0ns
        Capabilities: [178 v1] L1 PM Substates
                L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
                          PortCommonModeRestoreTime=150us PortTPowerOnTime=150us
                L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
                           T_CommonMode=0us LTR1.2_Threshold=0ns
                L1SubCtl2: T_PwrOn=10us
02:00.2 0700: 10ec:816b (rev 0e)
[...same...]

Signed-off-by: Tobias Diedrich <tobiasdiedrich@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200914173628.GA22508@yamamaya.is-a-geek.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: qcom_geni_serial: Drop __init from qcom_geni_console_setup 2020-09-09T17:14:07+00:00 John Stultz john.stultz@linaro.org 2020-08-11T02:50:44+00:00 87371d8581013aa6cf8987565a54c0ac3694774d [ Upstream commit 975efc66d4e654207c17f939eb737ac591ac38fe ] When booting with heavily modularized config, the serial console may not be able to load until after init when modules that satisfy needed dependencies have time to load. Unfortunately, as qcom_geni_console_setup is marked as __init, the function may have been freed before we get to run it, causing boot time crashes such as: [ 6.469057] Unable to handle kernel paging request at virtual address ffffffe645d4e6cc [ 6.481623] Mem abort info: [ 6.484466] ESR = 0x86000007 [ 6.487557] EC = 0x21: IABT (current EL), IL = 32 bits [ 6.492929] SET = 0, FnV = 0g [ 6.496016] EA = 0, S1PTW = 0 [ 6.499202] swapper pgtable: 4k pages, 39-bit VAs, pgdp=000000008151e000 [ 6.501286] ufshcd-qcom 1d84000.ufshc: ufshcd_print_pwr_info:[RX, TX]: gear=[3, 3], lane[2, 2], pwr[FAST MODE, FAST MODE], rate = 2 [ 6.505977] [ffffffe645d4e6cc] pgd=000000017df9f003, p4d=000000017df9f003, pud=000000017df9f003, pmd=000000017df9c003, pte=0000000000000000 [ 6.505990] Internal error: Oops: 86000007 [#1] PREEMPT SMP [ 6.505995] Modules linked in: zl10353 zl10039 zl10036 zd1301_demod xc5000 xc4000 ves1x93 ves1820 tuner_xc2028 tuner_simple tuner_types tua9001 tua6100 1 [ 6.506152] isl6405 [ 6.518104] ufshcd-qcom 1d84000.ufshc: ufshcd_find_max_sup_active_icc_level: Regulator capability was not set, actvIccLevel=0 [ 6.530549] horus3a helene fc2580 fc0013 fc0012 fc0011 ec100 e4000 dvb_pll ds3000 drxk drxd drx39xyj dib9000 dib8000 dib7000p dib7000m dib3000mc dibx003 [ 6.624271] CPU: 7 PID: 148 Comm: kworker/7:2 Tainted: G W 5.8.0-mainline-12021-g6defd37ba1cd #3455 [ 6.624273] Hardware name: Thundercomm Dragonboard 845c (DT) [ 6.624290] Workqueue: events deferred_probe_work_func [ 6.624296] pstate: 40c00005 (nZcv daif +PAN +UAO BTYPE=--) [ 6.624307] pc : qcom_geni_console_setup+0x0/0x110 [ 6.624316] lr : try_enable_new_console+0xa0/0x140 [ 6.624318] sp : ffffffc010843a30 [ 6.624320] x29: ffffffc010843a30 x28: ffffffe645c3e7d0 [ 6.624325] x27: ffffff80f8022180 x26: ffffffc010843b28 [ 6.637937] x25: 0000000000000000 x24: ffffffe6462a2000 [ 6.637941] x23: ffffffe646398000 x22: 0000000000000000 [ 6.637945] x21: 0000000000000000 x20: ffffffe6462a5ce8 [ 6.637952] x19: ffffffe646398e38 x18: ffffffffffffffff [ 6.680296] x17: 0000000000000000 x16: ffffffe64492b900 [ 6.680300] x15: ffffffe6461e9d08 x14: 69202930203d2064 [ 6.680305] x13: 7561625f65736162 x12: 202c363331203d20 [ 6.696434] x11: 0000000000000030 x10: 0101010101010101 [ 6.696438] x9 : 4d4d20746120304d x8 : 7f7f7f7f7f7f7f7f [ 6.707249] x7 : feff4c524c787373 x6 : 0000000000008080 [ 6.707253] x5 : 0000000000000000 x4 : 8080000000000000 [ 6.707257] x3 : 0000000000000000 x2 : ffffffe645d4e6cc [ 6.744223] qcom_geni_serial 898000.serial: dev_pm_opp_set_rate: failed to find OPP for freq 102400000 (-34) [ 6.744966] x1 : fffffffefe74e174 x0 : ffffffe6462a5ce8 [ 6.753580] qcom_geni_serial 898000.serial: dev_pm_opp_set_rate: failed to find OPP for freq 102400000 (-34) [ 6.761634] Call trace: [ 6.761639] qcom_geni_console_setup+0x0/0x110 [ 6.761645] register_console+0x29c/0x2f8 [ 6.767981] Bluetooth: hci0: Frame reassembly failed (-84) [ 6.775252] uart_add_one_port+0x438/0x500 [ 6.775258] qcom_geni_serial_probe+0x2c4/0x4a8 [ 6.775266] platform_drv_probe+0x58/0xa8 [ 6.855359] really_probe+0xec/0x398 [ 6.855362] driver_probe_device+0x5c/0xb8 [ 6.855367] __device_attach_driver+0x98/0xb8 [ 7.184945] bus_for_each_drv+0x74/0xd8 [ 7.188825] __device_attach+0xec/0x148 [ 7.192705] device_initial_probe+0x24/0x30 [ 7.196937] bus_probe_device+0x9c/0xa8 [ 7.200816] deferred_probe_work_func+0x7c/0xb8 [ 7.205398] process_one_work+0x20c/0x4b0 [ 7.209456] worker_thread+0x48/0x460 [ 7.213157] kthread+0x14c/0x158 [ 7.216432] ret_from_fork+0x10/0x18 [ 7.220049] Code: bad PC value [ 7.223139] ---[ end trace 73f3b21e251d5a70 ]--- Thus this patch removes the __init avoiding crash in such configs. Cc: Andy Gross <agross@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Saravana Kannan <saravanak@google.com> Cc: Todd Kjos <tkjos@google.com> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: linux-arm-msm@vger.kernel.org Cc: linux-serial@vger.kernel.org Suggested-by: Saravana Kannan <saravanak@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Link: https://lore.kernel.org/r/20200811025044.70626-1-john.stultz@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 975efc66d4e654207c17f939eb737ac591ac38fe ]

When booting with heavily modularized config, the serial console
may not be able to load until after init when modules that
satisfy needed dependencies have time to load.

Unfortunately, as qcom_geni_console_setup is marked as __init,
the function may have been freed before we get to run it,
causing boot time crashes such as:

[    6.469057] Unable to handle kernel paging request at virtual address ffffffe645d4e6cc
[    6.481623] Mem abort info:
[    6.484466]   ESR = 0x86000007
[    6.487557]   EC = 0x21: IABT (current EL), IL = 32 bits
[    6.492929]   SET = 0, FnV = 0g
[    6.496016]   EA = 0, S1PTW = 0
[    6.499202] swapper pgtable: 4k pages, 39-bit VAs, pgdp=000000008151e000
[    6.501286] ufshcd-qcom 1d84000.ufshc: ufshcd_print_pwr_info:[RX, TX]: gear=[3, 3], lane[2, 2], pwr[FAST MODE, FAST MODE], rate = 2
[    6.505977] [ffffffe645d4e6cc] pgd=000000017df9f003, p4d=000000017df9f003, pud=000000017df9f003, pmd=000000017df9c003, pte=0000000000000000
[    6.505990] Internal error: Oops: 86000007 [#1] PREEMPT SMP
[    6.505995] Modules linked in: zl10353 zl10039 zl10036 zd1301_demod xc5000 xc4000 ves1x93 ves1820 tuner_xc2028 tuner_simple tuner_types tua9001 tua6100 1
[    6.506152]  isl6405
[    6.518104] ufshcd-qcom 1d84000.ufshc: ufshcd_find_max_sup_active_icc_level: Regulator capability was not set, actvIccLevel=0
[    6.530549]  horus3a helene fc2580 fc0013 fc0012 fc0011 ec100 e4000 dvb_pll ds3000 drxk drxd drx39xyj dib9000 dib8000 dib7000p dib7000m dib3000mc dibx003
[    6.624271] CPU: 7 PID: 148 Comm: kworker/7:2 Tainted: G        W       5.8.0-mainline-12021-g6defd37ba1cd #3455
[    6.624273] Hardware name: Thundercomm Dragonboard 845c (DT)
[    6.624290] Workqueue: events deferred_probe_work_func
[    6.624296] pstate: 40c00005 (nZcv daif +PAN +UAO BTYPE=--)
[    6.624307] pc : qcom_geni_console_setup+0x0/0x110
[    6.624316] lr : try_enable_new_console+0xa0/0x140
[    6.624318] sp : ffffffc010843a30
[    6.624320] x29: ffffffc010843a30 x28: ffffffe645c3e7d0
[    6.624325] x27: ffffff80f8022180 x26: ffffffc010843b28
[    6.637937] x25: 0000000000000000 x24: ffffffe6462a2000
[    6.637941] x23: ffffffe646398000 x22: 0000000000000000
[    6.637945] x21: 0000000000000000 x20: ffffffe6462a5ce8
[    6.637952] x19: ffffffe646398e38 x18: ffffffffffffffff
[    6.680296] x17: 0000000000000000 x16: ffffffe64492b900
[    6.680300] x15: ffffffe6461e9d08 x14: 69202930203d2064
[    6.680305] x13: 7561625f65736162 x12: 202c363331203d20
[    6.696434] x11: 0000000000000030 x10: 0101010101010101
[    6.696438] x9 : 4d4d20746120304d x8 : 7f7f7f7f7f7f7f7f
[    6.707249] x7 : feff4c524c787373 x6 : 0000000000008080
[    6.707253] x5 : 0000000000000000 x4 : 8080000000000000
[    6.707257] x3 : 0000000000000000 x2 : ffffffe645d4e6cc
[    6.744223] qcom_geni_serial 898000.serial: dev_pm_opp_set_rate: failed to find OPP for freq 102400000 (-34)
[    6.744966] x1 : fffffffefe74e174 x0 : ffffffe6462a5ce8
[    6.753580] qcom_geni_serial 898000.serial: dev_pm_opp_set_rate: failed to find OPP for freq 102400000 (-34)
[    6.761634] Call trace:
[    6.761639]  qcom_geni_console_setup+0x0/0x110
[    6.761645]  register_console+0x29c/0x2f8
[    6.767981] Bluetooth: hci0: Frame reassembly failed (-84)
[    6.775252]  uart_add_one_port+0x438/0x500
[    6.775258]  qcom_geni_serial_probe+0x2c4/0x4a8
[    6.775266]  platform_drv_probe+0x58/0xa8
[    6.855359]  really_probe+0xec/0x398
[    6.855362]  driver_probe_device+0x5c/0xb8
[    6.855367]  __device_attach_driver+0x98/0xb8
[    7.184945]  bus_for_each_drv+0x74/0xd8
[    7.188825]  __device_attach+0xec/0x148
[    7.192705]  device_initial_probe+0x24/0x30
[    7.196937]  bus_probe_device+0x9c/0xa8
[    7.200816]  deferred_probe_work_func+0x7c/0xb8
[    7.205398]  process_one_work+0x20c/0x4b0
[    7.209456]  worker_thread+0x48/0x460
[    7.213157]  kthread+0x14c/0x158
[    7.216432]  ret_from_fork+0x10/0x18
[    7.220049] Code: bad PC value
[    7.223139] ---[ end trace 73f3b21e251d5a70 ]---

Thus this patch removes the __init avoiding crash in such
configs.

Cc: Andy Gross <agross@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Suggested-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200811025044.70626-1-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: 8250: change lock order in serial8250_do_startup() 2020-09-03T09:29:41+00:00 Sergey Senozhatsky sergey.senozhatsky@gmail.com 2020-08-17T02:26:46+00:00 116790cfa0b8b8ae801d282166059691b33c965a commit 205d300aea75623e1ae4aa43e0d265ab9cf195fd upstream. We have a number of "uart.port->desc.lock vs desc.lock->uart.port" lockdep reports coming from 8250 driver; this causes a bit of trouble to people, so let's fix it. The problem is reverse lock order in two different call paths: chain #1: serial8250_do_startup() spin_lock_irqsave(&port->lock); disable_irq_nosync(port->irq); raw_spin_lock_irqsave(&desc->lock) chain #2: __report_bad_irq() raw_spin_lock_irqsave(&desc->lock) for_each_action_of_desc() printk() spin_lock_irqsave(&port->lock); Fix this by changing the order of locks in serial8250_do_startup(): do disable_irq_nosync() first, which grabs desc->lock, and grab uart->port after that, so that chain #1 and chain #2 have same lock order. Full lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.4.39 #55 Not tainted ====================================================== swapper/0/0 is trying to acquire lock: ffffffffab65b6c0 (console_owner){-...}, at: console_lock_spinning_enable+0x31/0x57 but task is already holding lock: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&irq_desc_lock_class){-.-.}: _raw_spin_lock_irqsave+0x61/0x8d __irq_get_desc_lock+0x65/0x89 __disable_irq_nosync+0x3b/0x93 serial8250_do_startup+0x451/0x75c uart_startup+0x1b4/0x2ff uart_port_activate+0x73/0xa0 tty_port_open+0xae/0x10a uart_open+0x1b/0x26 tty_open+0x24d/0x3a0 chrdev_open+0xd5/0x1cc do_dentry_open+0x299/0x3c8 path_openat+0x434/0x1100 do_filp_open+0x9b/0x10a do_sys_open+0x15f/0x3d7 kernel_init_freeable+0x157/0x1dd kernel_init+0xe/0x105 ret_from_fork+0x27/0x50 -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x61/0x8d serial8250_console_write+0xa7/0x2a0 console_unlock+0x3b7/0x528 vprintk_emit+0x111/0x17f printk+0x59/0x73 register_console+0x336/0x3a4 uart_add_one_port+0x51b/0x5be serial8250_register_8250_port+0x454/0x55e dw8250_probe+0x4dc/0x5b9 platform_drv_probe+0x67/0x8b really_probe+0x14a/0x422 driver_probe_device+0x66/0x130 device_driver_attach+0x42/0x5b __driver_attach+0xca/0x139 bus_for_each_dev+0x97/0xc9 bus_add_driver+0x12b/0x228 driver_register+0x64/0xed do_one_initcall+0x20c/0x4a6 do_initcall_level+0xb5/0xc5 do_basic_setup+0x4c/0x58 kernel_init_freeable+0x13f/0x1dd kernel_init+0xe/0x105 ret_from_fork+0x27/0x50 -> #0 (console_owner){-...}: __lock_acquire+0x118d/0x2714 lock_acquire+0x203/0x258 console_lock_spinning_enable+0x51/0x57 console_unlock+0x25d/0x528 vprintk_emit+0x111/0x17f printk+0x59/0x73 __report_bad_irq+0xa3/0xba note_interrupt+0x19a/0x1d6 handle_irq_event_percpu+0x57/0x79 handle_irq_event+0x36/0x55 handle_fasteoi_irq+0xc2/0x18a do_IRQ+0xb3/0x157 ret_from_intr+0x0/0x1d cpuidle_enter_state+0x12f/0x1fd cpuidle_enter+0x2e/0x3d do_idle+0x1ce/0x2ce cpu_startup_entry+0x1d/0x1f start_kernel+0x406/0x46a secondary_startup_64+0xa4/0xb0 other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &irq_desc_lock_class Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&irq_desc_lock_class); lock(&port_lock_key); lock(&irq_desc_lock_class); lock(console_owner); *** DEADLOCK *** 2 locks held by swapper/0/0: #0: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba #1: ffffffffab65b5c0 (console_lock){+.+.}, at: console_trylock_spinning+0x20/0x181 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.39 #55 Hardware name: XXXXXX Call Trace: <IRQ> dump_stack+0xbf/0x133 ? print_circular_bug+0xd6/0xe9 check_noncircular+0x1b9/0x1c3 __lock_acquire+0x118d/0x2714 lock_acquire+0x203/0x258 ? console_lock_spinning_enable+0x31/0x57 console_lock_spinning_enable+0x51/0x57 ? console_lock_spinning_enable+0x31/0x57 console_unlock+0x25d/0x528 ? console_trylock+0x18/0x4e vprintk_emit+0x111/0x17f ? lock_acquire+0x203/0x258 printk+0x59/0x73 __report_bad_irq+0xa3/0xba note_interrupt+0x19a/0x1d6 handle_irq_event_percpu+0x57/0x79 handle_irq_event+0x36/0x55 handle_fasteoi_irq+0xc2/0x18a do_IRQ+0xb3/0x157 common_interrupt+0xf/0xf </IRQ> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Fixes: 768aec0b5bcc ("serial: 8250: fix shared interrupts issues with SMP and RT kernels") Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Raul Rangel <rrangel@google.com> BugLink: https://bugs.chromium.org/p/chromium/issues/detail?id=1114800 Link: https://lore.kernel.org/lkml/CAHQZ30BnfX+gxjPm1DUd5psOTqbyDh4EJE=2=VAMW_VDafctkA@mail.gmail.com/T/#u Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200817022646.1484638-1-sergey.senozhatsky@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 205d300aea75623e1ae4aa43e0d265ab9cf195fd upstream.

We have a number of "uart.port->desc.lock vs desc.lock->uart.port"
lockdep reports coming from 8250 driver; this causes a bit of trouble
to people, so let's fix it.

The problem is reverse lock order in two different call paths:

chain #1:

 serial8250_do_startup()
  spin_lock_irqsave(&port->lock);
   disable_irq_nosync(port->irq);
    raw_spin_lock_irqsave(&desc->lock)

chain #2:

  __report_bad_irq()
   raw_spin_lock_irqsave(&desc->lock)
    for_each_action_of_desc()
     printk()
      spin_lock_irqsave(&port->lock);

Fix this by changing the order of locks in serial8250_do_startup():
 do disable_irq_nosync() first, which grabs desc->lock, and grab
 uart->port after that, so that chain #1 and chain #2 have same lock
 order.

Full lockdep splat:

 ======================================================
 WARNING: possible circular locking dependency detected
 5.4.39 #55 Not tainted
 ======================================================

 swapper/0/0 is trying to acquire lock:
 ffffffffab65b6c0 (console_owner){-...}, at: console_lock_spinning_enable+0x31/0x57

 but task is already holding lock:
 ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (&irq_desc_lock_class){-.-.}:
        _raw_spin_lock_irqsave+0x61/0x8d
        __irq_get_desc_lock+0x65/0x89
        __disable_irq_nosync+0x3b/0x93
        serial8250_do_startup+0x451/0x75c
        uart_startup+0x1b4/0x2ff
        uart_port_activate+0x73/0xa0
        tty_port_open+0xae/0x10a
        uart_open+0x1b/0x26
        tty_open+0x24d/0x3a0
        chrdev_open+0xd5/0x1cc
        do_dentry_open+0x299/0x3c8
        path_openat+0x434/0x1100
        do_filp_open+0x9b/0x10a
        do_sys_open+0x15f/0x3d7
        kernel_init_freeable+0x157/0x1dd
        kernel_init+0xe/0x105
        ret_from_fork+0x27/0x50

 -> #1 (&port_lock_key){-.-.}:
        _raw_spin_lock_irqsave+0x61/0x8d
        serial8250_console_write+0xa7/0x2a0
        console_unlock+0x3b7/0x528
        vprintk_emit+0x111/0x17f
        printk+0x59/0x73
        register_console+0x336/0x3a4
        uart_add_one_port+0x51b/0x5be
        serial8250_register_8250_port+0x454/0x55e
        dw8250_probe+0x4dc/0x5b9
        platform_drv_probe+0x67/0x8b
        really_probe+0x14a/0x422
        driver_probe_device+0x66/0x130
        device_driver_attach+0x42/0x5b
        __driver_attach+0xca/0x139
        bus_for_each_dev+0x97/0xc9
        bus_add_driver+0x12b/0x228
        driver_register+0x64/0xed
        do_one_initcall+0x20c/0x4a6
        do_initcall_level+0xb5/0xc5
        do_basic_setup+0x4c/0x58
        kernel_init_freeable+0x13f/0x1dd
        kernel_init+0xe/0x105
        ret_from_fork+0x27/0x50

 -> #0 (console_owner){-...}:
        __lock_acquire+0x118d/0x2714
        lock_acquire+0x203/0x258
        console_lock_spinning_enable+0x51/0x57
        console_unlock+0x25d/0x528
        vprintk_emit+0x111/0x17f
        printk+0x59/0x73
        __report_bad_irq+0xa3/0xba
        note_interrupt+0x19a/0x1d6
        handle_irq_event_percpu+0x57/0x79
        handle_irq_event+0x36/0x55
        handle_fasteoi_irq+0xc2/0x18a
        do_IRQ+0xb3/0x157
        ret_from_intr+0x0/0x1d
        cpuidle_enter_state+0x12f/0x1fd
        cpuidle_enter+0x2e/0x3d
        do_idle+0x1ce/0x2ce
        cpu_startup_entry+0x1d/0x1f
        start_kernel+0x406/0x46a
        secondary_startup_64+0xa4/0xb0

 other info that might help us debug this:

 Chain exists of:
   console_owner --> &port_lock_key --> &irq_desc_lock_class

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&irq_desc_lock_class);
                                lock(&port_lock_key);
                                lock(&irq_desc_lock_class);
   lock(console_owner);

  *** DEADLOCK ***

 2 locks held by swapper/0/0:
  #0: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba
  #1: ffffffffab65b5c0 (console_lock){+.+.}, at: console_trylock_spinning+0x20/0x181

 stack backtrace:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.39 #55
 Hardware name: XXXXXX
 Call Trace:
  <IRQ>
  dump_stack+0xbf/0x133
  ? print_circular_bug+0xd6/0xe9
  check_noncircular+0x1b9/0x1c3
  __lock_acquire+0x118d/0x2714
  lock_acquire+0x203/0x258
  ? console_lock_spinning_enable+0x31/0x57
  console_lock_spinning_enable+0x51/0x57
  ? console_lock_spinning_enable+0x31/0x57
  console_unlock+0x25d/0x528
  ? console_trylock+0x18/0x4e
  vprintk_emit+0x111/0x17f
  ? lock_acquire+0x203/0x258
  printk+0x59/0x73
  __report_bad_irq+0xa3/0xba
  note_interrupt+0x19a/0x1d6
  handle_irq_event_percpu+0x57/0x79
  handle_irq_event+0x36/0x55
  handle_fasteoi_irq+0xc2/0x18a
  do_IRQ+0xb3/0x157
  common_interrupt+0xf/0xf
  </IRQ>

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Fixes: 768aec0b5bcc ("serial: 8250: fix shared interrupts issues with SMP and RT kernels")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Raul Rangel <rrangel@google.com>
BugLink: https://bugs.chromium.org/p/chromium/issues/detail?id=1114800
Link: https://lore.kernel.org/lkml/CAHQZ30BnfX+gxjPm1DUd5psOTqbyDh4EJE=2=VAMW_VDafctkA@mail.gmail.com/T/#u
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200817022646.1484638-1-sergey.senozhatsky@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>