October 2024 - Linux-stable-mirror

[PATCH 5.10.y 0/3] mptcp: fix recent failed backports

by Matthieu Baerts (NGI0)

Greg recently reported 2 patches that could not be applied without conflicts in v5.10: - e32d262c89e2 ("mptcp: handle consistently DSS corruption") - 4dabcdf58121 ("tcp: fix mptcp DSS corruption due to large pmtu xmit") Conflicts have been resolved, and documented in each patch. One extra commit has been backported, to support allow_infinite_fallback which is used by one commit from the list above: - 0530020a7c8f ("mptcp: track and update contiguous data status") Geliang Tang (1): mptcp: track and update contiguous data status Paolo Abeni (2): mptcp: handle consistently DSS corruption tcp: fix mptcp DSS corruption due to large pmtu xmit net/ipv4/tcp_output.c | 2 +- net/mptcp/mib.c | 2 ++ net/mptcp/mib.h | 2 ++ net/mptcp/protocol.c | 26 ++++++++++++++++++++++---- net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 3 ++- 6 files changed, 30 insertions(+), 6 deletions(-) -- 2.45.2

1 year, 2 months

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[PATCH 5.15.y 0/6] mptcp: fix recent failed backports

by Matthieu Baerts (NGI0)

Greg recently reported 6 patches that could not be applied without conflicts in v5.15: - e32d262c89e2 ("mptcp: handle consistently DSS corruption") - 4dabcdf58121 ("tcp: fix mptcp DSS corruption due to large pmtu xmit") - 119d51e225fe ("mptcp: fallback when MPTCP opts are dropped after 1st data") - 7decd1f5904a ("mptcp: pm: fix UaF read in mptcp_pm_nl_rm_addr_or_subflow") - 3d041393ea8c ("mptcp: prevent MPC handshake on port-based signal endpoints") - 5afca7e996c4 ("selftests: mptcp: join: test for prohibited MPC to port-based endp") Conflicts have been resolved for the 5 first ones, and documented in each patch. The last patch has not been backported: this is an extra test for the selftests validating the previous commit, and there are a lot of conflicts. That's fine not to backport this test, it is still possible to use the selftests from a newer version and run them on this older kernel. One extra commit has been backported, to support allow_infinite_fallback which is used by two commits from the list above: - 0530020a7c8f ("mptcp: track and update contiguous data status") Geliang Tang (1): mptcp: track and update contiguous data status Matthieu Baerts (NGI0) (2): mptcp: fallback when MPTCP opts are dropped after 1st data mptcp: pm: fix UaF read in mptcp_pm_nl_rm_addr_or_subflow Paolo Abeni (3): mptcp: handle consistently DSS corruption tcp: fix mptcp DSS corruption due to large pmtu xmit mptcp: prevent MPC handshake on port-based signal endpoints net/ipv4/tcp_output.c | 2 +- net/mptcp/mib.c | 3 +++ net/mptcp/mib.h | 3 +++ net/mptcp/pm_netlink.c | 3 ++- net/mptcp/protocol.c | 23 ++++++++++++++++++++--- net/mptcp/protocol.h | 2 ++ net/mptcp/subflow.c | 19 ++++++++++++++++--- 7 files changed, 47 insertions(+), 8 deletions(-) -- 2.45.2

1 year, 2 months

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[PATCH 6.1.y 0/2] mptcp: fix recent failed backports

by Matthieu Baerts (NGI0)

Greg recently reported 3 patches that could not be applied without conflicts in v6.1: - 4dabcdf58121 ("tcp: fix mptcp DSS corruption due to large pmtu xmit") - 3d041393ea8c ("mptcp: prevent MPC handshake on port-based signal endpoints") - 5afca7e996c4 ("selftests: mptcp: join: test for prohibited MPC to port-based endp") Conflicts have been resolved for the two first ones, and documented in each patch. The last patch has not been backported: this is an extra test for the selftests validating the previous commit, and there are a lot of conflicts. That's fine not to backport this test, it is still possible to use the selftests from a newer version and run them on this older kernel. Paolo Abeni (2): tcp: fix mptcp DSS corruption due to large pmtu xmit mptcp: prevent MPC handshake on port-based signal endpoints net/ipv4/tcp_output.c | 4 +--- net/mptcp/mib.c | 1 + net/mptcp/mib.h | 1 + net/mptcp/pm_netlink.c | 1 + net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 11 +++++++++++ 6 files changed, 16 insertions(+), 3 deletions(-) -- 2.45.2

1 year, 2 months

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[PATCH 6.6.y 0/4] mptcp: fix recent failed backports

by Matthieu Baerts (NGI0)

Greg recently reported 2 patches that could not be applied without conflict in v6.6: - 4dabcdf58121 ("tcp: fix mptcp DSS corruption due to large pmtu xmit") - 5afca7e996c4 ("selftests: mptcp: join: test for prohibited MPC to port-based endp") Conflicts have been resolved, and documented in each patch. Note that there are two extra patches: - 8c6f6b4bb53a ("selftests: mptcp: join: change capture/checksum as bool"): to avoid some conflicts - "selftests: mptcp: remove duplicated variables": a dedicated patch for v6.6, to fix some previous backport issues. Geliang Tang (1): selftests: mptcp: join: change capture/checksum as bool Matthieu Baerts (NGI0) (1): selftests: mptcp: remove duplicated variables Paolo Abeni (2): tcp: fix mptcp DSS corruption due to large pmtu xmit selftests: mptcp: join: test for prohibited MPC to port-based endp net/ipv4/tcp_output.c | 4 +- .../testing/selftests/net/mptcp/mptcp_join.sh | 135 ++++++++++++------ .../testing/selftests/net/mptcp/mptcp_lib.sh | 11 -- 3 files changed, 96 insertions(+), 54 deletions(-) -- 2.45.2

1 year, 2 months

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FAILED: patch "[PATCH] serial: qcom-geni: fix shutdown race" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 23f5f5debcaac1399cfeacec215278bf6dbc1d11 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024102142-pristine-mayday-9998@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 23f5f5debcaac1399cfeacec215278bf6dbc1d11 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Wed, 9 Oct 2024 16:51:04 +0200 Subject: [PATCH] serial: qcom-geni: fix shutdown race A commit adding back the stopping of tx on port shutdown failed to add back the locking which had also been removed by commit e83766334f96 ("tty: serial: qcom_geni_serial: No need to stop tx/rx on UART shutdown"). Holding the port lock is needed to serialise against the console code, which may update the interrupt enable register and access the port state. Fixes: d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") Fixes: 947cc4ecc06c ("serial: qcom-geni: fix soft lockup on sw flow control and suspend") Cc: stable(a)vger.kernel.org # 6.3 Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski(a)linaro.org> Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Reviewed-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/r/20241009145110.16847-4-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2e4a5361f137..87cd974b76bf 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1114,10 +1114,12 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); + uart_port_lock_irq(uport); qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); qcom_geni_serial_cancel_tx_cmd(uport); + uart_port_unlock_irq(uport); } static void qcom_geni_serial_flush_buffer(struct uart_port *uport)

1 year, 2 months

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[PATCH v2 0/2] Fix KASAN crash when using KASAN_VMALLOC

by Linus Walleij

This problem reported by Clement LE GOFFIC manifest when using CONFIG_KASAN_IN_VMALLOC and VMAP_STACK: https://lore.kernel.org/linux-arm-kernel/a1a1d062-f3a2-4d05-9836-3b098de9db… After some analysis it seems we are missing to sync the VMALLOC shadow memory in top level PGD to all CPUs. Add some code to perform this sync, and the bug appears to go away. As suggested by Ard, also perform a dummy read from the shadow memory of the new VMAP_STACK in the low level assembly. Signed-off-by: Linus Walleij <linus.walleij(a)linaro.org> --- Changes in v2: - Implement the two helper functions suggested by Russell making the KASAN PGD copying less messy. - Link to v1: https://lore.kernel.org/r/20241015-arm-kasan-vmalloc-crash-v1-0-dbb23592ca8… --- Linus Walleij (2): ARM: ioremap: Sync PGDs for VMALLOC shadow ARM: entry: Do a dummy read from VMAP shadow arch/arm/kernel/entry-armv.S | 8 ++++++++ arch/arm/mm/ioremap.c | 25 +++++++++++++++++++++---- 2 files changed, 29 insertions(+), 4 deletions(-) --- base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc change-id: 20241015-arm-kasan-vmalloc-crash-fcbd51416457 Best regards, -- Linus Walleij <linus.walleij(a)linaro.org>

1 year, 2 months

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FAILED: patch "[PATCH] serial: imx: Update mctrl old_status on RTSD interrupt" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 40d7903386df4d18f04d90510ba90eedee260085 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024102101-glacial-outsell-b7f5@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 40d7903386df4d18f04d90510ba90eedee260085 Mon Sep 17 00:00:00 2001 From: Marek Vasut <marex(a)denx.de> Date: Wed, 2 Oct 2024 20:40:38 +0200 Subject: [PATCH] serial: imx: Update mctrl old_status on RTSD interrupt When sending data using DMA at high baudrate (4 Mbdps in local test case) to a device with small RX buffer which keeps asserting RTS after every received byte, it is possible that the iMX UART driver would not recognize the falling edge of RTS input signal and get stuck, unable to transmit any more data. This condition happens when the following sequence of events occur: - imx_uart_mctrl_check() is called at some point and takes a snapshot of UART control signal status into sport->old_status using imx_uart_get_hwmctrl(). The RTSS/TIOCM_CTS bit is of interest here (*). - DMA transfer occurs, the remote device asserts RTS signal after each byte. The i.MX UART driver recognizes each such RTS signal change, raises an interrupt with USR1 register RTSD bit set, which leads to invocation of __imx_uart_rtsint(), which calls uart_handle_cts_change(). - If the RTS signal is deasserted, uart_handle_cts_change() clears port->hw_stopped and unblocks the port for further data transfers. - If the RTS is asserted, uart_handle_cts_change() sets port->hw_stopped and blocks the port for further data transfers. This may occur as the last interrupt of a transfer, which means port->hw_stopped remains set and the port remains blocked (**). - Any further data transfer attempts will trigger imx_uart_mctrl_check(), which will read current status of UART control signals by calling imx_uart_get_hwmctrl() (***) and compare it with sport->old_status . - If current status differs from sport->old_status for RTS signal, uart_handle_cts_change() is called and possibly unblocks the port by clearing port->hw_stopped . - If current status does not differ from sport->old_status for RTS signal, no action occurs. This may occur in case prior snapshot (*) was taken before any transfer so the RTS is deasserted, current snapshot (***) was taken after a transfer and therefore RTS is deasserted again, which means current status and sport->old_status are identical. In case (**) triggered when RTS got asserted, and made port->hw_stopped set, the port->hw_stopped will remain set because no change on RTS line is recognized by this driver and uart_handle_cts_change() is not called from here to unblock the port->hw_stopped. Update sport->old_status in __imx_uart_rtsint() accordingly to make imx_uart_mctrl_check() detect such RTS change. Note that TIOCM_CAR and TIOCM_RI bits in sport->old_status do not suffer from this problem. Fixes: ceca629e0b48 ("[ARM] 2971/1: i.MX uart handle rts irq") Cc: stable <stable(a)kernel.org> Reviewed-by: Esben Haabendal <esben(a)geanix.com> Signed-off-by: Marek Vasut <marex(a)denx.de> Link: https://lore.kernel.org/r/20241002184133.19427-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 67d4a72eda77..90974d338f3c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -762,6 +762,21 @@ static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id) imx_uart_writel(sport, USR1_RTSD, USR1); usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS; + /* + * Update sport->old_status here, so any follow-up calls to + * imx_uart_mctrl_check() will be able to recognize that RTS + * state changed since last imx_uart_mctrl_check() call. + * + * In case RTS has been detected as asserted here and later on + * deasserted by the time imx_uart_mctrl_check() was called, + * imx_uart_mctrl_check() can detect the RTS state change and + * trigger uart_handle_cts_change() to unblock the port for + * further TX transfers. + */ + if (usr1 & USR1_RTSS) + sport->old_status |= TIOCM_CTS; + else + sport->old_status &= ~TIOCM_CTS; uart_handle_cts_change(&sport->port, usr1); wake_up_interruptible(&sport->port.state->port.delta_msr_wait);

1 year, 2 months

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FAILED: patch "[PATCH] serial: imx: Update mctrl old_status on RTSD interrupt" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 40d7903386df4d18f04d90510ba90eedee260085 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024102100-unselect-chevron-960a@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 40d7903386df4d18f04d90510ba90eedee260085 Mon Sep 17 00:00:00 2001 From: Marek Vasut <marex(a)denx.de> Date: Wed, 2 Oct 2024 20:40:38 +0200 Subject: [PATCH] serial: imx: Update mctrl old_status on RTSD interrupt When sending data using DMA at high baudrate (4 Mbdps in local test case) to a device with small RX buffer which keeps asserting RTS after every received byte, it is possible that the iMX UART driver would not recognize the falling edge of RTS input signal and get stuck, unable to transmit any more data. This condition happens when the following sequence of events occur: - imx_uart_mctrl_check() is called at some point and takes a snapshot of UART control signal status into sport->old_status using imx_uart_get_hwmctrl(). The RTSS/TIOCM_CTS bit is of interest here (*). - DMA transfer occurs, the remote device asserts RTS signal after each byte. The i.MX UART driver recognizes each such RTS signal change, raises an interrupt with USR1 register RTSD bit set, which leads to invocation of __imx_uart_rtsint(), which calls uart_handle_cts_change(). - If the RTS signal is deasserted, uart_handle_cts_change() clears port->hw_stopped and unblocks the port for further data transfers. - If the RTS is asserted, uart_handle_cts_change() sets port->hw_stopped and blocks the port for further data transfers. This may occur as the last interrupt of a transfer, which means port->hw_stopped remains set and the port remains blocked (**). - Any further data transfer attempts will trigger imx_uart_mctrl_check(), which will read current status of UART control signals by calling imx_uart_get_hwmctrl() (***) and compare it with sport->old_status . - If current status differs from sport->old_status for RTS signal, uart_handle_cts_change() is called and possibly unblocks the port by clearing port->hw_stopped . - If current status does not differ from sport->old_status for RTS signal, no action occurs. This may occur in case prior snapshot (*) was taken before any transfer so the RTS is deasserted, current snapshot (***) was taken after a transfer and therefore RTS is deasserted again, which means current status and sport->old_status are identical. In case (**) triggered when RTS got asserted, and made port->hw_stopped set, the port->hw_stopped will remain set because no change on RTS line is recognized by this driver and uart_handle_cts_change() is not called from here to unblock the port->hw_stopped. Update sport->old_status in __imx_uart_rtsint() accordingly to make imx_uart_mctrl_check() detect such RTS change. Note that TIOCM_CAR and TIOCM_RI bits in sport->old_status do not suffer from this problem. Fixes: ceca629e0b48 ("[ARM] 2971/1: i.MX uart handle rts irq") Cc: stable <stable(a)kernel.org> Reviewed-by: Esben Haabendal <esben(a)geanix.com> Signed-off-by: Marek Vasut <marex(a)denx.de> Link: https://lore.kernel.org/r/20241002184133.19427-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 67d4a72eda77..90974d338f3c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -762,6 +762,21 @@ static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id) imx_uart_writel(sport, USR1_RTSD, USR1); usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS; + /* + * Update sport->old_status here, so any follow-up calls to + * imx_uart_mctrl_check() will be able to recognize that RTS + * state changed since last imx_uart_mctrl_check() call. + * + * In case RTS has been detected as asserted here and later on + * deasserted by the time imx_uart_mctrl_check() was called, + * imx_uart_mctrl_check() can detect the RTS state change and + * trigger uart_handle_cts_change() to unblock the port for + * further TX transfers. + */ + if (usr1 & USR1_RTSS) + sport->old_status |= TIOCM_CTS; + else + sport->old_status &= ~TIOCM_CTS; uart_handle_cts_change(&sport->port, usr1); wake_up_interruptible(&sport->port.state->port.delta_msr_wait);

1 year, 2 months

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FAILED: patch "[PATCH] serial: imx: Update mctrl old_status on RTSD interrupt" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 40d7903386df4d18f04d90510ba90eedee260085 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024102158-vanquish-ignition-83d0@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 40d7903386df4d18f04d90510ba90eedee260085 Mon Sep 17 00:00:00 2001 From: Marek Vasut <marex(a)denx.de> Date: Wed, 2 Oct 2024 20:40:38 +0200 Subject: [PATCH] serial: imx: Update mctrl old_status on RTSD interrupt When sending data using DMA at high baudrate (4 Mbdps in local test case) to a device with small RX buffer which keeps asserting RTS after every received byte, it is possible that the iMX UART driver would not recognize the falling edge of RTS input signal and get stuck, unable to transmit any more data. This condition happens when the following sequence of events occur: - imx_uart_mctrl_check() is called at some point and takes a snapshot of UART control signal status into sport->old_status using imx_uart_get_hwmctrl(). The RTSS/TIOCM_CTS bit is of interest here (*). - DMA transfer occurs, the remote device asserts RTS signal after each byte. The i.MX UART driver recognizes each such RTS signal change, raises an interrupt with USR1 register RTSD bit set, which leads to invocation of __imx_uart_rtsint(), which calls uart_handle_cts_change(). - If the RTS signal is deasserted, uart_handle_cts_change() clears port->hw_stopped and unblocks the port for further data transfers. - If the RTS is asserted, uart_handle_cts_change() sets port->hw_stopped and blocks the port for further data transfers. This may occur as the last interrupt of a transfer, which means port->hw_stopped remains set and the port remains blocked (**). - Any further data transfer attempts will trigger imx_uart_mctrl_check(), which will read current status of UART control signals by calling imx_uart_get_hwmctrl() (***) and compare it with sport->old_status . - If current status differs from sport->old_status for RTS signal, uart_handle_cts_change() is called and possibly unblocks the port by clearing port->hw_stopped . - If current status does not differ from sport->old_status for RTS signal, no action occurs. This may occur in case prior snapshot (*) was taken before any transfer so the RTS is deasserted, current snapshot (***) was taken after a transfer and therefore RTS is deasserted again, which means current status and sport->old_status are identical. In case (**) triggered when RTS got asserted, and made port->hw_stopped set, the port->hw_stopped will remain set because no change on RTS line is recognized by this driver and uart_handle_cts_change() is not called from here to unblock the port->hw_stopped. Update sport->old_status in __imx_uart_rtsint() accordingly to make imx_uart_mctrl_check() detect such RTS change. Note that TIOCM_CAR and TIOCM_RI bits in sport->old_status do not suffer from this problem. Fixes: ceca629e0b48 ("[ARM] 2971/1: i.MX uart handle rts irq") Cc: stable <stable(a)kernel.org> Reviewed-by: Esben Haabendal <esben(a)geanix.com> Signed-off-by: Marek Vasut <marex(a)denx.de> Link: https://lore.kernel.org/r/20241002184133.19427-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 67d4a72eda77..90974d338f3c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -762,6 +762,21 @@ static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id) imx_uart_writel(sport, USR1_RTSD, USR1); usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS; + /* + * Update sport->old_status here, so any follow-up calls to + * imx_uart_mctrl_check() will be able to recognize that RTS + * state changed since last imx_uart_mctrl_check() call. + * + * In case RTS has been detected as asserted here and later on + * deasserted by the time imx_uart_mctrl_check() was called, + * imx_uart_mctrl_check() can detect the RTS state change and + * trigger uart_handle_cts_change() to unblock the port for + * further TX transfers. + */ + if (usr1 & USR1_RTSS) + sport->old_status |= TIOCM_CTS; + else + sport->old_status &= ~TIOCM_CTS; uart_handle_cts_change(&sport->port, usr1); wake_up_interruptible(&sport->port.state->port.delta_msr_wait);

1 year, 2 months

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FAILED: patch "[PATCH] serial: imx: Update mctrl old_status on RTSD interrupt" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 40d7903386df4d18f04d90510ba90eedee260085 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024102157-tactical-darkened-7877@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 40d7903386df4d18f04d90510ba90eedee260085 Mon Sep 17 00:00:00 2001 From: Marek Vasut <marex(a)denx.de> Date: Wed, 2 Oct 2024 20:40:38 +0200 Subject: [PATCH] serial: imx: Update mctrl old_status on RTSD interrupt When sending data using DMA at high baudrate (4 Mbdps in local test case) to a device with small RX buffer which keeps asserting RTS after every received byte, it is possible that the iMX UART driver would not recognize the falling edge of RTS input signal and get stuck, unable to transmit any more data. This condition happens when the following sequence of events occur: - imx_uart_mctrl_check() is called at some point and takes a snapshot of UART control signal status into sport->old_status using imx_uart_get_hwmctrl(). The RTSS/TIOCM_CTS bit is of interest here (*). - DMA transfer occurs, the remote device asserts RTS signal after each byte. The i.MX UART driver recognizes each such RTS signal change, raises an interrupt with USR1 register RTSD bit set, which leads to invocation of __imx_uart_rtsint(), which calls uart_handle_cts_change(). - If the RTS signal is deasserted, uart_handle_cts_change() clears port->hw_stopped and unblocks the port for further data transfers. - If the RTS is asserted, uart_handle_cts_change() sets port->hw_stopped and blocks the port for further data transfers. This may occur as the last interrupt of a transfer, which means port->hw_stopped remains set and the port remains blocked (**). - Any further data transfer attempts will trigger imx_uart_mctrl_check(), which will read current status of UART control signals by calling imx_uart_get_hwmctrl() (***) and compare it with sport->old_status . - If current status differs from sport->old_status for RTS signal, uart_handle_cts_change() is called and possibly unblocks the port by clearing port->hw_stopped . - If current status does not differ from sport->old_status for RTS signal, no action occurs. This may occur in case prior snapshot (*) was taken before any transfer so the RTS is deasserted, current snapshot (***) was taken after a transfer and therefore RTS is deasserted again, which means current status and sport->old_status are identical. In case (**) triggered when RTS got asserted, and made port->hw_stopped set, the port->hw_stopped will remain set because no change on RTS line is recognized by this driver and uart_handle_cts_change() is not called from here to unblock the port->hw_stopped. Update sport->old_status in __imx_uart_rtsint() accordingly to make imx_uart_mctrl_check() detect such RTS change. Note that TIOCM_CAR and TIOCM_RI bits in sport->old_status do not suffer from this problem. Fixes: ceca629e0b48 ("[ARM] 2971/1: i.MX uart handle rts irq") Cc: stable <stable(a)kernel.org> Reviewed-by: Esben Haabendal <esben(a)geanix.com> Signed-off-by: Marek Vasut <marex(a)denx.de> Link: https://lore.kernel.org/r/20241002184133.19427-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 67d4a72eda77..90974d338f3c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -762,6 +762,21 @@ static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id) imx_uart_writel(sport, USR1_RTSD, USR1); usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS; + /* + * Update sport->old_status here, so any follow-up calls to + * imx_uart_mctrl_check() will be able to recognize that RTS + * state changed since last imx_uart_mctrl_check() call. + * + * In case RTS has been detected as asserted here and later on + * deasserted by the time imx_uart_mctrl_check() was called, + * imx_uart_mctrl_check() can detect the RTS state change and + * trigger uart_handle_cts_change() to unblock the port for + * further TX transfers. + */ + if (usr1 & USR1_RTSS) + sport->old_status |= TIOCM_CTS; + else + sport->old_status &= ~TIOCM_CTS; uart_handle_cts_change(&sport->port, usr1); wake_up_interruptible(&sport->port.state->port.delta_msr_wait);

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