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FAILED: patch "[PATCH] serial: 8250: fix panic due to PSLVERR" 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 7f8fdd4dbffc05982b96caf586f77a014b2a9353 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081849-trio-prepay-4247@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f8fdd4dbffc05982b96caf586f77a014b2a9353 Mon Sep 17 00:00:00 2001 From: Yunhui Cui <cuiyunhui(a)bytedance.com> Date: Wed, 23 Jul 2025 10:33:22 +0800 Subject: [PATCH] serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70 Fixes: c49436b657d0 ("serial: 8250_dw: Improve unwritable LCR workaround") Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/ Signed-off-by: Yunhui Cui <cuiyunhui(a)bytedance.com> Reviewed-by: John Ogness <john.ogness(a)linutronix.de> Cc: stable <stable(a)kernel.org> Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7eddcab318b4..2da9db960d09 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2269,9 +2269,9 @@ static void serial8250_initialize(struct uart_port *port) { unsigned long flags; + uart_port_lock_irqsave(port, &flags); serial_port_out(port, UART_LCR, UART_LCR_WLEN8); - uart_port_lock_irqsave(port, &flags); serial8250_init_mctrl(port); serial8250_iir_txen_test(port); uart_port_unlock_irqrestore(port, flags);

4 weeks, 1 day

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[PATCH net-next v3 2/5] sctp: Fix MAC comparison to be constant-time

by Eric Biggers

To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)kernel.org> --- net/sctp/sm_make_chunk.c | 3 ++- net/sctp/sm_statefuns.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c index 3ead591c72fd3..d099b605e44a7 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -29,10 +29,11 @@ */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <crypto/hash.h> +#include <crypto/utils.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/net.h> @@ -1786,11 +1787,11 @@ struct sctp_association *sctp_unpack_cookie( *error = -SCTP_IERROR_NOMEM; goto fail; } } - if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) { + if (crypto_memneq(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) { *error = -SCTP_IERROR_BAD_SIG; goto fail; } no_hmac: diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index a0524ba8d7878..d4d5b14b49b3f 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -28,10 +28,11 @@ * Kevin Gao <kevin.gao(a)intel.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <crypto/utils.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/net.h> @@ -4414,11 +4415,11 @@ static enum sctp_ierror sctp_sf_authenticate( sctp_auth_calculate_hmac(asoc, chunk->skb, (struct sctp_auth_chunk *)chunk->chunk_hdr, sh_key, GFP_ATOMIC); /* Discard the packet if the digests do not match */ - if (memcmp(save_digest, digest, sig_len)) { + if (crypto_memneq(save_digest, digest, sig_len)) { kfree(save_digest); return SCTP_IERROR_BAD_SIG; } kfree(save_digest); -- 2.50.1

4 weeks, 1 day

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FAILED: patch "[PATCH] usb: typec: fusb302: cache PD RX state" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081832-rental-utter-f3e1@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 Mon Sep 17 00:00:00 2001 From: Sebastian Reichel <sebastian.reichel(a)collabora.com> Date: Fri, 4 Jul 2025 19:55:06 +0200 Subject: [PATCH] usb: typec: fusb302: cache PD RX state This patch fixes a race condition communication error, which ends up in PD hard resets when losing the race. Some systems, like the Radxa ROCK 5B are powered through USB-C without any backup power source and use a FUSB302 chip to do the PD negotiation. This means it is quite important to avoid hard resets, since that effectively kills the system's power-supply. I've found the following race condition while debugging unplanned power loss during booting the board every now and then: 1. lots of TCPM/FUSB302/PD initialization stuff 2. TCPM ends up in SNK_WAIT_CAPABILITIES (tcpm_set_pd_rx is enabled here) 3. the remote PD source does not send anything, so TCPM does a SOFT RESET 4. TCPM ends up in SNK_WAIT_CAPABILITIES for the second time (tcpm_set_pd_rx is enabled again, even though it is still on) At this point I've seen broken CRC good messages being send by the FUSB302 with a logic analyzer sniffing the CC lines. Also it looks like messages are being lost and things generally going haywire with one of the two sides doing a hard reset once a broken CRC good message was send to the bus. I think the system is running into a race condition, that the FIFOs are being cleared and/or the automatic good CRC message generation flag is being updated while a message is already arriving. Let's avoid this by caching the PD RX enabled state, as we have already processed anything in the FIFOs and are in a good state. As a side effect that this also optimizes I2C bus usage :) As far as I can tell the problem theoretically also exists when TCPM enters SNK_WAIT_CAPABILITIES the first time, but I believe this is less critical for the following reason: On devices like the ROCK 5B, which are powered through a TCPM backed USB-C port, the bootloader must have done some prior PD communication (initial communication must happen within 5 seconds after plugging the USB-C plug). This means the first time the kernel TCPM state machine reaches SNK_WAIT_CAPABILITIES, the remote side is not sending messages actively. On other devices a hard reset simply adds some extra delay and things should be good afterwards. Fixes: c034a43e72dda ("staging: typec: Fairchild FUSB302 Type-c chip driver") Cc: stable <stable(a)kernel.org> Signed-off-by: Sebastian Reichel <sebastian.reichel(a)collabora.com> Reviewed-by: Heikki Krogerus <heikki.krogerus(a)linux.intel.com> Link: https://lore.kernel.org/r/20250704-fusb302-race-condition-fix-v1-1-239012c0… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index f2801279c4b5..a4ff2403ddd6 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -104,6 +104,7 @@ struct fusb302_chip { bool vconn_on; bool vbus_on; bool charge_on; + bool pd_rx_on; bool vbus_present; enum typec_cc_polarity cc_polarity; enum typec_cc_status cc1; @@ -841,6 +842,11 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) int ret = 0; mutex_lock(&chip->lock); + if (chip->pd_rx_on == on) { + fusb302_log(chip, "pd is already %s", str_on_off(on)); + goto done; + } + ret = fusb302_pd_rx_flush(chip); if (ret < 0) { fusb302_log(chip, "cannot flush pd rx buffer, ret=%d", ret); @@ -863,6 +869,8 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) str_on_off(on), ret); goto done; } + + chip->pd_rx_on = on; fusb302_log(chip, "pd := %s", str_on_off(on)); done: mutex_unlock(&chip->lock);

4 weeks, 1 day

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[PATCH net-next 1/3] ipv6: sr: Fix MAC comparison to be constant-time

by Eric Biggers

To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)kernel.org> --- net/ipv6/seg6_hmac.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c index f78ecb6ad8383..5dae892bbc73b 100644 --- a/net/ipv6/seg6_hmac.c +++ b/net/ipv6/seg6_hmac.c @@ -33,10 +33,11 @@ #include <net/ip6_route.h> #include <net/addrconf.h> #include <net/xfrm.h> #include <crypto/hash.h> +#include <crypto/utils.h> #include <net/seg6.h> #include <net/genetlink.h> #include <net/seg6_hmac.h> #include <linux/random.h> @@ -278,11 +279,11 @@ bool seg6_hmac_validate_skb(struct sk_buff *skb) return false; if (seg6_hmac_compute(hinfo, srh, &ipv6_hdr(skb)->saddr, hmac_output)) return false; - if (memcmp(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN) != 0) + if (crypto_memneq(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN)) return false; return true; } EXPORT_SYMBOL(seg6_hmac_validate_skb); -- 2.50.1

4 weeks, 1 day

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FAILED: patch "[PATCH] serial: 8250: fix panic due to PSLVERR" 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 7f8fdd4dbffc05982b96caf586f77a014b2a9353 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081848-lemon-attic-be0e@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f8fdd4dbffc05982b96caf586f77a014b2a9353 Mon Sep 17 00:00:00 2001 From: Yunhui Cui <cuiyunhui(a)bytedance.com> Date: Wed, 23 Jul 2025 10:33:22 +0800 Subject: [PATCH] serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70 Fixes: c49436b657d0 ("serial: 8250_dw: Improve unwritable LCR workaround") Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/ Signed-off-by: Yunhui Cui <cuiyunhui(a)bytedance.com> Reviewed-by: John Ogness <john.ogness(a)linutronix.de> Cc: stable <stable(a)kernel.org> Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7eddcab318b4..2da9db960d09 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2269,9 +2269,9 @@ static void serial8250_initialize(struct uart_port *port) { unsigned long flags; + uart_port_lock_irqsave(port, &flags); serial_port_out(port, UART_LCR, UART_LCR_WLEN8); - uart_port_lock_irqsave(port, &flags); serial8250_init_mctrl(port); serial8250_iir_txen_test(port); uart_port_unlock_irqrestore(port, flags);

4 weeks, 1 day

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FAILED: patch "[PATCH] usb: typec: fusb302: cache PD RX state" 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 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081831-untrimmed-dab-6b43@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 Mon Sep 17 00:00:00 2001 From: Sebastian Reichel <sebastian.reichel(a)collabora.com> Date: Fri, 4 Jul 2025 19:55:06 +0200 Subject: [PATCH] usb: typec: fusb302: cache PD RX state This patch fixes a race condition communication error, which ends up in PD hard resets when losing the race. Some systems, like the Radxa ROCK 5B are powered through USB-C without any backup power source and use a FUSB302 chip to do the PD negotiation. This means it is quite important to avoid hard resets, since that effectively kills the system's power-supply. I've found the following race condition while debugging unplanned power loss during booting the board every now and then: 1. lots of TCPM/FUSB302/PD initialization stuff 2. TCPM ends up in SNK_WAIT_CAPABILITIES (tcpm_set_pd_rx is enabled here) 3. the remote PD source does not send anything, so TCPM does a SOFT RESET 4. TCPM ends up in SNK_WAIT_CAPABILITIES for the second time (tcpm_set_pd_rx is enabled again, even though it is still on) At this point I've seen broken CRC good messages being send by the FUSB302 with a logic analyzer sniffing the CC lines. Also it looks like messages are being lost and things generally going haywire with one of the two sides doing a hard reset once a broken CRC good message was send to the bus. I think the system is running into a race condition, that the FIFOs are being cleared and/or the automatic good CRC message generation flag is being updated while a message is already arriving. Let's avoid this by caching the PD RX enabled state, as we have already processed anything in the FIFOs and are in a good state. As a side effect that this also optimizes I2C bus usage :) As far as I can tell the problem theoretically also exists when TCPM enters SNK_WAIT_CAPABILITIES the first time, but I believe this is less critical for the following reason: On devices like the ROCK 5B, which are powered through a TCPM backed USB-C port, the bootloader must have done some prior PD communication (initial communication must happen within 5 seconds after plugging the USB-C plug). This means the first time the kernel TCPM state machine reaches SNK_WAIT_CAPABILITIES, the remote side is not sending messages actively. On other devices a hard reset simply adds some extra delay and things should be good afterwards. Fixes: c034a43e72dda ("staging: typec: Fairchild FUSB302 Type-c chip driver") Cc: stable <stable(a)kernel.org> Signed-off-by: Sebastian Reichel <sebastian.reichel(a)collabora.com> Reviewed-by: Heikki Krogerus <heikki.krogerus(a)linux.intel.com> Link: https://lore.kernel.org/r/20250704-fusb302-race-condition-fix-v1-1-239012c0… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index f2801279c4b5..a4ff2403ddd6 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -104,6 +104,7 @@ struct fusb302_chip { bool vconn_on; bool vbus_on; bool charge_on; + bool pd_rx_on; bool vbus_present; enum typec_cc_polarity cc_polarity; enum typec_cc_status cc1; @@ -841,6 +842,11 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) int ret = 0; mutex_lock(&chip->lock); + if (chip->pd_rx_on == on) { + fusb302_log(chip, "pd is already %s", str_on_off(on)); + goto done; + } + ret = fusb302_pd_rx_flush(chip); if (ret < 0) { fusb302_log(chip, "cannot flush pd rx buffer, ret=%d", ret); @@ -863,6 +869,8 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) str_on_off(on), ret); goto done; } + + chip->pd_rx_on = on; fusb302_log(chip, "pd := %s", str_on_off(on)); done: mutex_unlock(&chip->lock);

4 weeks, 1 day

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FAILED: patch "[PATCH] serial: 8250: fix panic due to PSLVERR" 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 7f8fdd4dbffc05982b96caf586f77a014b2a9353 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081848-charter-handcart-4eda@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f8fdd4dbffc05982b96caf586f77a014b2a9353 Mon Sep 17 00:00:00 2001 From: Yunhui Cui <cuiyunhui(a)bytedance.com> Date: Wed, 23 Jul 2025 10:33:22 +0800 Subject: [PATCH] serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70 Fixes: c49436b657d0 ("serial: 8250_dw: Improve unwritable LCR workaround") Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/ Signed-off-by: Yunhui Cui <cuiyunhui(a)bytedance.com> Reviewed-by: John Ogness <john.ogness(a)linutronix.de> Cc: stable <stable(a)kernel.org> Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7eddcab318b4..2da9db960d09 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2269,9 +2269,9 @@ static void serial8250_initialize(struct uart_port *port) { unsigned long flags; + uart_port_lock_irqsave(port, &flags); serial_port_out(port, UART_LCR, UART_LCR_WLEN8); - uart_port_lock_irqsave(port, &flags); serial8250_init_mctrl(port); serial8250_iir_txen_test(port); uart_port_unlock_irqrestore(port, flags);

4 weeks, 1 day

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FAILED: patch "[PATCH] serial: 8250: fix panic due to PSLVERR" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 7f8fdd4dbffc05982b96caf586f77a014b2a9353 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081847-cheddar-glacier-ea0e@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f8fdd4dbffc05982b96caf586f77a014b2a9353 Mon Sep 17 00:00:00 2001 From: Yunhui Cui <cuiyunhui(a)bytedance.com> Date: Wed, 23 Jul 2025 10:33:22 +0800 Subject: [PATCH] serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70 Fixes: c49436b657d0 ("serial: 8250_dw: Improve unwritable LCR workaround") Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/ Signed-off-by: Yunhui Cui <cuiyunhui(a)bytedance.com> Reviewed-by: John Ogness <john.ogness(a)linutronix.de> Cc: stable <stable(a)kernel.org> Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7eddcab318b4..2da9db960d09 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2269,9 +2269,9 @@ static void serial8250_initialize(struct uart_port *port) { unsigned long flags; + uart_port_lock_irqsave(port, &flags); serial_port_out(port, UART_LCR, UART_LCR_WLEN8); - uart_port_lock_irqsave(port, &flags); serial8250_init_mctrl(port); serial8250_iir_txen_test(port); uart_port_unlock_irqrestore(port, flags);

4 weeks, 1 day

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FAILED: patch "[PATCH] serial: 8250: fix panic due to PSLVERR" 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 7f8fdd4dbffc05982b96caf586f77a014b2a9353 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081846-exquisite-previous-f76e@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7f8fdd4dbffc05982b96caf586f77a014b2a9353 Mon Sep 17 00:00:00 2001 From: Yunhui Cui <cuiyunhui(a)bytedance.com> Date: Wed, 23 Jul 2025 10:33:22 +0800 Subject: [PATCH] serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70 Fixes: c49436b657d0 ("serial: 8250_dw: Improve unwritable LCR workaround") Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/ Signed-off-by: Yunhui Cui <cuiyunhui(a)bytedance.com> Reviewed-by: John Ogness <john.ogness(a)linutronix.de> Cc: stable <stable(a)kernel.org> Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7eddcab318b4..2da9db960d09 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2269,9 +2269,9 @@ static void serial8250_initialize(struct uart_port *port) { unsigned long flags; + uart_port_lock_irqsave(port, &flags); serial_port_out(port, UART_LCR, UART_LCR_WLEN8); - uart_port_lock_irqsave(port, &flags); serial8250_init_mctrl(port); serial8250_iir_txen_test(port); uart_port_unlock_irqrestore(port, flags);

4 weeks, 1 day

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FAILED: patch "[PATCH] usb: typec: fusb302: cache PD RX state" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-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-6.12.y git checkout FETCH_HEAD git cherry-pick -x 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081830-selected-dandelion-46ec@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 Mon Sep 17 00:00:00 2001 From: Sebastian Reichel <sebastian.reichel(a)collabora.com> Date: Fri, 4 Jul 2025 19:55:06 +0200 Subject: [PATCH] usb: typec: fusb302: cache PD RX state This patch fixes a race condition communication error, which ends up in PD hard resets when losing the race. Some systems, like the Radxa ROCK 5B are powered through USB-C without any backup power source and use a FUSB302 chip to do the PD negotiation. This means it is quite important to avoid hard resets, since that effectively kills the system's power-supply. I've found the following race condition while debugging unplanned power loss during booting the board every now and then: 1. lots of TCPM/FUSB302/PD initialization stuff 2. TCPM ends up in SNK_WAIT_CAPABILITIES (tcpm_set_pd_rx is enabled here) 3. the remote PD source does not send anything, so TCPM does a SOFT RESET 4. TCPM ends up in SNK_WAIT_CAPABILITIES for the second time (tcpm_set_pd_rx is enabled again, even though it is still on) At this point I've seen broken CRC good messages being send by the FUSB302 with a logic analyzer sniffing the CC lines. Also it looks like messages are being lost and things generally going haywire with one of the two sides doing a hard reset once a broken CRC good message was send to the bus. I think the system is running into a race condition, that the FIFOs are being cleared and/or the automatic good CRC message generation flag is being updated while a message is already arriving. Let's avoid this by caching the PD RX enabled state, as we have already processed anything in the FIFOs and are in a good state. As a side effect that this also optimizes I2C bus usage :) As far as I can tell the problem theoretically also exists when TCPM enters SNK_WAIT_CAPABILITIES the first time, but I believe this is less critical for the following reason: On devices like the ROCK 5B, which are powered through a TCPM backed USB-C port, the bootloader must have done some prior PD communication (initial communication must happen within 5 seconds after plugging the USB-C plug). This means the first time the kernel TCPM state machine reaches SNK_WAIT_CAPABILITIES, the remote side is not sending messages actively. On other devices a hard reset simply adds some extra delay and things should be good afterwards. Fixes: c034a43e72dda ("staging: typec: Fairchild FUSB302 Type-c chip driver") Cc: stable <stable(a)kernel.org> Signed-off-by: Sebastian Reichel <sebastian.reichel(a)collabora.com> Reviewed-by: Heikki Krogerus <heikki.krogerus(a)linux.intel.com> Link: https://lore.kernel.org/r/20250704-fusb302-race-condition-fix-v1-1-239012c0… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index f2801279c4b5..a4ff2403ddd6 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -104,6 +104,7 @@ struct fusb302_chip { bool vconn_on; bool vbus_on; bool charge_on; + bool pd_rx_on; bool vbus_present; enum typec_cc_polarity cc_polarity; enum typec_cc_status cc1; @@ -841,6 +842,11 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) int ret = 0; mutex_lock(&chip->lock); + if (chip->pd_rx_on == on) { + fusb302_log(chip, "pd is already %s", str_on_off(on)); + goto done; + } + ret = fusb302_pd_rx_flush(chip); if (ret < 0) { fusb302_log(chip, "cannot flush pd rx buffer, ret=%d", ret); @@ -863,6 +869,8 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) str_on_off(on), ret); goto done; } + + chip->pd_rx_on = on; fusb302_log(chip, "pd := %s", str_on_off(on)); done: mutex_unlock(&chip->lock);

4 weeks, 1 day

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