October 2019 - Linux-stable-mirror

[PATCH 6/8] xhci: Prevent deadlock when xhci adapter breaks during init

by Mathias Nyman

From: Bill Kuzeja <William.Kuzeja(a)stratus.com> The system can hit a deadlock if an xhci adapter breaks while initializing. The deadlock is between two threads: thread 1 is tearing down the adapter and is stuck in usb_unlocked_disable_lpm waiting to lock the hcd->handwidth_mutex. Thread 2 is holding this mutex (while still trying to add a usb device), but is stuck in xhci_endpoint_reset waiting for a stop or config command to complete. A reboot is required to resolve. It turns out when calling xhci_queue_stop_endpoint and xhci_queue_configure_endpoint in xhci_endpoint_reset, the return code is not checked for errors. If the timing is right and the adapter dies just before either of these commands get issued, we hang indefinitely waiting for a completion on a command that didn't get issued. This wasn't a problem before the following fix because we didn't send commands in xhci_endpoint_reset: commit f5249461b504 ("xhci: Clear the host side toggle manually when endpoint is soft reset") With the patch I am submitting, a duration test which breaks adapters during initialization (and which deadlocks with the standard kernel) runs without issue. Fixes: f5249461b504 ("xhci: Clear the host side toggle manually when endpoint is soft reset") Cc: <stable(a)vger.kernel.org> # v4.17+ Cc: Torez Smith <torez(a)redhat.com> Signed-off-by: Bill Kuzeja <william.kuzeja(a)stratus.com> Signed-off-by: Torez Smith <torez(a)redhat.com> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index fe8f9ff58015..8c068d0cc7c1 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3095,6 +3095,7 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, unsigned int ep_index; unsigned long flags; u32 ep_flag; + int err; xhci = hcd_to_xhci(hcd); if (!host_ep->hcpriv) @@ -3154,7 +3155,17 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, xhci_free_command(xhci, cfg_cmd); goto cleanup; } - xhci_queue_stop_endpoint(xhci, stop_cmd, udev->slot_id, ep_index, 0); + + err = xhci_queue_stop_endpoint(xhci, stop_cmd, udev->slot_id, + ep_index, 0); + if (err < 0) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_free_command(xhci, cfg_cmd); + xhci_dbg(xhci, "%s: Failed to queue stop ep command, %d ", + __func__, err); + goto cleanup; + } + xhci_ring_cmd_db(xhci); spin_unlock_irqrestore(&xhci->lock, flags); @@ -3168,8 +3179,16 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, ctrl_ctx, ep_flag, ep_flag); xhci_endpoint_copy(xhci, cfg_cmd->in_ctx, vdev->out_ctx, ep_index); - xhci_queue_configure_endpoint(xhci, cfg_cmd, cfg_cmd->in_ctx->dma, + err = xhci_queue_configure_endpoint(xhci, cfg_cmd, cfg_cmd->in_ctx->dma, udev->slot_id, false); + if (err < 0) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_free_command(xhci, cfg_cmd); + xhci_dbg(xhci, "%s: Failed to queue config ep command, %d ", + __func__, err); + goto cleanup; + } + xhci_ring_cmd_db(xhci); spin_unlock_irqrestore(&xhci->lock, flags); -- 2.7.4

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[PATCH 5/8] usb: xhci: wait for CNR controller not ready bit in xhci resume

by Mathias Nyman

From: Rick Tseng <rtseng(a)nvidia.com> NVIDIA 3.1 xHCI card would lose power when moving power state into D3Cold. Thus we need to wait for CNR bit to clear in xhci resume, just as in xhci init. [Minor changes to comment and commit message -Mathias] Cc: <stable(a)vger.kernel.org> Signed-off-by: Rick Tseng <rtseng(a)nvidia.com> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index aec69d294973..fe8f9ff58015 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1108,6 +1108,18 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) hibernated = true; if (!hibernated) { + /* + * Some controllers might lose power during suspend, so wait + * for controller not ready bit to clear, just as in xHC init. + */ + retval = xhci_handshake(&xhci->op_regs->status, + STS_CNR, 0, 10 * 1000 * 1000); + if (retval) { + xhci_warn(xhci, "Controller not ready at resume %d\n", + retval); + spin_unlock_irq(&xhci->lock); + return retval; + } /* step 1: restore register */ xhci_restore_registers(xhci); /* step 2: initialize command ring buffer */ -- 2.7.4

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[PATCH 4/8] xhci: Fix USB 3.1 capability detection on early xHCI 1.1 spec based hosts

by Mathias Nyman

Early xHCI 1.1 spec did not mention USB 3.1 capable hosts should set sbrn to 0x31, or that the minor revision is a two digit BCD containing minor and sub-minor numbers. This was later clarified in xHCI 1.2. Some USB 3.1 capable hosts therefore have sbrn set to 0x30, or minor revision set to 0x1 instead of 0x10. Detect the USB 3.1 capability correctly for these hosts as well Fixes: ddd57980a0fd ("xhci: detect USB 3.2 capable host controllers correctly") Cc: <stable(a)vger.kernel.org> # v4.18+ Cc: Loïc Yhuel <loic.yhuel(a)gmail.com> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index a5ba5ace3d00..aec69d294973 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -5079,11 +5079,18 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks) hcd->has_tt = 1; } else { /* - * Some 3.1 hosts return sbrn 0x30, use xhci supported protocol - * minor revision instead of sbrn. Minor revision is a two digit - * BCD containing minor and sub-minor numbers, only show minor. + * Early xHCI 1.1 spec did not mention USB 3.1 capable hosts + * should return 0x31 for sbrn, or that the minor revision + * is a two digit BCD containig minor and sub-minor numbers. + * This was later clarified in xHCI 1.2. + * + * Some USB 3.1 capable hosts therefore have sbrn 0x30, and + * minor revision set to 0x1 instead of 0x10. */ - minor_rev = xhci->usb3_rhub.min_rev / 0x10; + if (xhci->usb3_rhub.min_rev == 0x1) + minor_rev = 1; + else + minor_rev = xhci->usb3_rhub.min_rev / 0x10; switch (minor_rev) { case 2: -- 2.7.4

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[PATCH 3/8] xhci: Check all endpoints for LPM timeout

by Mathias Nyman

From: Jan Schmidt <jan(a)centricular.com> If an endpoint is encountered that returns USB3_LPM_DEVICE_INITIATED, keep checking further endpoints, as there might be periodic endpoints later that return USB3_LPM_DISABLED due to shorter service intervals. Without this, the code can set too high a maximum-exit-latency and prevent the use of multiple USB3 cameras that should be able to work. Cc: <stable(a)vger.kernel.org> Signed-off-by: Jan Schmidt <jan(a)centricular.com> Tested-by: Philipp Zabel <p.zabel(a)pengutronix.de> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index aed5a65f25bd..a5ba5ace3d00 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4674,12 +4674,12 @@ static int xhci_update_timeout_for_endpoint(struct xhci_hcd *xhci, alt_timeout = xhci_call_host_update_timeout_for_endpoint(xhci, udev, desc, state, timeout); - /* If we found we can't enable hub-initiated LPM, or + /* If we found we can't enable hub-initiated LPM, and * the U1 or U2 exit latency was too high to allow - * device-initiated LPM as well, just stop searching. + * device-initiated LPM as well, then we will disable LPM + * for this device, so stop searching any further. */ - if (alt_timeout == USB3_LPM_DISABLED || - alt_timeout == USB3_LPM_DEVICE_INITIATED) { + if (alt_timeout == USB3_LPM_DISABLED) { *timeout = alt_timeout; return -E2BIG; } -- 2.7.4

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[PATCH 2/8] xhci: Prevent device initiated U1/U2 link pm if exit latency is too long

by Mathias Nyman

If host/hub initiated link pm is prevented by a driver flag we still must ensure that periodic endpoints have longer service intervals than link pm exit latency before allowing device initiated link pm. Fix this by continue walking and checking endpoint service interval if xhci_get_timeout_no_hub_lpm() returns anything else than USB3_LPM_DISABLED While at it fix the split line error message Tested-by: Jan Schmidt <jan(a)centricular.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 500865975687..aed5a65f25bd 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4790,10 +4790,12 @@ static u16 xhci_calculate_lpm_timeout(struct usb_hcd *hcd, if (intf->dev.driver) { driver = to_usb_driver(intf->dev.driver); if (driver && driver->disable_hub_initiated_lpm) { - dev_dbg(&udev->dev, "Hub-initiated %s disabled " - "at request of driver %s\n", - state_name, driver->name); - return xhci_get_timeout_no_hub_lpm(udev, state); + dev_dbg(&udev->dev, "Hub-initiated %s disabled at request of driver %s\n", + state_name, driver->name); + timeout = xhci_get_timeout_no_hub_lpm(udev, + state); + if (timeout == USB3_LPM_DISABLED) + return timeout; } } -- 2.7.4

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[PATCH 1/8] xhci: Fix false warning message about wrong bounce buffer write length

by Mathias Nyman

The check printing out the "WARN Wrong bounce buffer write length:" uses incorrect values when comparing bytes written from scatterlist to bounce buffer. Actual copied lengths are fine. The used seg->bounce_len will be set to equal new_buf_len a few lines later in the code, but is incorrect when doing the comparison. The patch which added this false warning was backported to 4.8+ kernels so this should be backported as far as well. Cc: <stable(a)vger.kernel.org> # v4.8+ Fixes: 597c56e372da ("xhci: update bounce buffer with correct sg num") Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci-ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9741cdeea9d7..85ceb43e3405 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3202,10 +3202,10 @@ static int xhci_align_td(struct xhci_hcd *xhci, struct urb *urb, u32 enqd_len, if (usb_urb_dir_out(urb)) { len = sg_pcopy_to_buffer(urb->sg, urb->num_sgs, seg->bounce_buf, new_buff_len, enqd_len); - if (len != seg->bounce_len) + if (len != new_buff_len) xhci_warn(xhci, "WARN Wrong bounce buffer write length: %zu != %d\n", - len, seg->bounce_len); + len, new_buff_len); seg->bounce_dma = dma_map_single(dev, seg->bounce_buf, max_pkt, DMA_TO_DEVICE); } else { -- 2.7.4

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[PATCH 1/4] mfd: rk808: fix rk818 ID template

by Heiko Stuebner

From: Daniel Schultz <d.schultz(a)phytec.de> The Rockchip PMIC driver can automatically detect connected component versions by reading the ID_MSB and ID_LSB registers. The probe function will always fail with RK818 PMICs because the ID_MSK is 0xFFF0 and the RK818 template ID is 0x8181. This patch changes this value to 0x8180. Fixes: 9d6105e19f61 ("mfd: rk808: Fix up the chip id get failed") Cc: stable(a)vger.kernel.org Cc: Elaine Zhang <zhangqing(a)rock-chips.com> Cc: Joseph Chen <chenjh(a)rock-chips.com> Signed-off-by: Daniel Schultz <d.schultz(a)phytec.de> Acked-by: Lee Jones <lee.jones(a)linaro.org> [resend as it seems to have dropped on the floor] Signed-off-by: Heiko Stuebner <heiko(a)sntech.de> --- include/linux/mfd/rk808.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h index 7cfd2b0504df..a59bf323f713 100644 --- a/include/linux/mfd/rk808.h +++ b/include/linux/mfd/rk808.h @@ -610,7 +610,7 @@ enum { RK808_ID = 0x0000, RK809_ID = 0x8090, RK817_ID = 0x8170, - RK818_ID = 0x8181, + RK818_ID = 0x8180, }; struct rk808 { -- 2.20.1

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[PATCH 2/2] usb: typec: ucsi: displayport: Fix for the mode entering routine

by Heikki Krogerus

Making sure that ucsi_displayport_enter() function does not return an error if the displayport alternate mode has already been entered. It's normal that the firmware (or controller) has already entered the alternate mode by the time the operating system is notified about the device. Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode") Cc: stable(a)vger.kernel.org Signed-off-by: Heikki Krogerus <heikki.krogerus(a)linux.intel.com> --- drivers/usb/typec/ucsi/displayport.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c index 6c103697c582..d99700cb4dca 100644 --- a/drivers/usb/typec/ucsi/displayport.c +++ b/drivers/usb/typec/ucsi/displayport.c @@ -75,6 +75,8 @@ static int ucsi_displayport_enter(struct typec_altmode *alt) if (cur != 0xff) { mutex_unlock(&dp->con->lock); + if (dp->con->port_altmode[cur] == alt) + return 0; return -EBUSY; } -- 2.23.0

5 years

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[PATCH 1/2] usb: typec: ucsi: ccg: Remove run_isr flag

by Heikki Krogerus

The "run_isr" flag is used for preventing the driver from calling the interrupt service routine in its runtime resume callback when the driver is expecting completion to a command, but what that basically does is that it hides the real problem. The real problem is that the controller is allowed to suspend in the middle of command execution. As a more appropriate fix for the problem, using autosuspend delay time that matches UCSI_TIMEOUT_MS (5s). That prevents the controller from suspending while still in the middle of executing a command. This fixes a potential deadlock. Both ccg_read() and ccg_write() are called with the mutex already taken at least from ccg_send_command(). In ccg_read() and ccg_write, the mutex is only acquired so that run_isr flag can be set. Fixes: f0e4cd948b91 ("usb: typec: ucsi: ccg: add runtime pm workaround") Cc: stable(a)vger.kernel.org Signed-off-by: Heikki Krogerus <heikki.krogerus(a)linux.intel.com> --- drivers/usb/typec/ucsi/ucsi_ccg.c | 42 +++---------------------------- 1 file changed, 4 insertions(+), 38 deletions(-) diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c index 907e20e1a71e..d772fce51905 100644 --- a/drivers/usb/typec/ucsi/ucsi_ccg.c +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c @@ -195,7 +195,6 @@ struct ucsi_ccg { /* fw build with vendor information */ u16 fw_build; - bool run_isr; /* flag to call ISR routine during resume */ struct work_struct pm_work; }; @@ -224,18 +223,6 @@ static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len) if (quirks && quirks->max_read_len) max_read_len = quirks->max_read_len; - if (uc->fw_build == CCG_FW_BUILD_NVIDIA && - uc->fw_version <= CCG_OLD_FW_VERSION) { - mutex_lock(&uc->lock); - /* - * Do not schedule pm_work to run ISR in - * ucsi_ccg_runtime_resume() after pm_runtime_get_sync() - * since we are already in ISR path. - */ - uc->run_isr = false; - mutex_unlock(&uc->lock); - } - pm_runtime_get_sync(uc->dev); while (rem_len > 0) { msgs[1].buf = &data[len - rem_len]; @@ -278,18 +265,6 @@ static int ccg_write(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len) msgs[0].len = len + sizeof(rab); msgs[0].buf = buf; - if (uc->fw_build == CCG_FW_BUILD_NVIDIA && - uc->fw_version <= CCG_OLD_FW_VERSION) { - mutex_lock(&uc->lock); - /* - * Do not schedule pm_work to run ISR in - * ucsi_ccg_runtime_resume() after pm_runtime_get_sync() - * since we are already in ISR path. - */ - uc->run_isr = false; - mutex_unlock(&uc->lock); - } - pm_runtime_get_sync(uc->dev); status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (status < 0) { @@ -1130,7 +1105,6 @@ static int ucsi_ccg_probe(struct i2c_client *client, uc->ppm.sync = ucsi_ccg_sync; uc->dev = dev; uc->client = client; - uc->run_isr = true; mutex_init(&uc->lock); INIT_WORK(&uc->work, ccg_update_firmware); INIT_WORK(&uc->pm_work, ccg_pm_workaround_work); @@ -1188,6 +1162,8 @@ static int ucsi_ccg_probe(struct i2c_client *client, pm_runtime_set_active(uc->dev); pm_runtime_enable(uc->dev); + pm_runtime_use_autosuspend(uc->dev); + pm_runtime_set_autosuspend_delay(uc->dev, 5000); pm_runtime_idle(uc->dev); return 0; @@ -1229,7 +1205,6 @@ static int ucsi_ccg_runtime_resume(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct ucsi_ccg *uc = i2c_get_clientdata(client); - bool schedule = true; /* * Firmware version 3.1.10 or earlier, built for NVIDIA has known issue @@ -1237,17 +1212,8 @@ static int ucsi_ccg_runtime_resume(struct device *dev) * Schedule a work to call ISR as a workaround. */ if (uc->fw_build == CCG_FW_BUILD_NVIDIA && - uc->fw_version <= CCG_OLD_FW_VERSION) { - mutex_lock(&uc->lock); - if (!uc->run_isr) { - uc->run_isr = true; - schedule = false; - } - mutex_unlock(&uc->lock); - - if (schedule) - schedule_work(&uc->pm_work); - } + uc->fw_version <= CCG_OLD_FW_VERSION) + schedule_work(&uc->pm_work); return 0; } -- 2.23.0

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patch "USB: usblcd: fix I/O after disconnect" added to usb-linus

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled USB: usblcd: fix I/O after disconnect to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From eb7f5a490c5edfe8126f64bc58b9ba2edef0a425 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan(a)kernel.org> Date: Thu, 26 Sep 2019 11:12:25 +0200 Subject: USB: usblcd: fix I/O after disconnect Make sure to stop all I/O on disconnect by adding a disconnected flag which is used to prevent new I/O from being started and by stopping all ongoing I/O before returning. This also fixes a potential use-after-free on driver unbind in case the driver data is freed before the completion handler has run. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable <stable(a)vger.kernel.org> # 7bbe990c989e Signed-off-by: Johan Hovold <johan(a)kernel.org> Link: https://lore.kernel.org/r/20190926091228.24634-7-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/usb/misc/usblcd.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c index 9ba4a4e68d91..aa982d3ca36b 100644 --- a/drivers/usb/misc/usblcd.c +++ b/drivers/usb/misc/usblcd.c @@ -18,6 +18,7 @@ #include <linux/slab.h> #include <linux/errno.h> #include <linux/mutex.h> +#include <linux/rwsem.h> #include <linux/uaccess.h> #include <linux/usb.h> @@ -57,6 +58,8 @@ struct usb_lcd { using up all RAM */ struct usb_anchor submitted; /* URBs to wait for before suspend */ + struct rw_semaphore io_rwsem; + unsigned long disconnected:1; }; #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref) @@ -142,6 +145,13 @@ static ssize_t lcd_read(struct file *file, char __user * buffer, dev = file->private_data; + down_read(&dev->io_rwsem); + + if (dev->disconnected) { + retval = -ENODEV; + goto out_up_io; + } + /* do a blocking bulk read to get data from the device */ retval = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, @@ -158,6 +168,9 @@ static ssize_t lcd_read(struct file *file, char __user * buffer, retval = bytes_read; } +out_up_io: + up_read(&dev->io_rwsem); + return retval; } @@ -237,11 +250,18 @@ static ssize_t lcd_write(struct file *file, const char __user * user_buffer, if (r < 0) return -EINTR; + down_read(&dev->io_rwsem); + + if (dev->disconnected) { + retval = -ENODEV; + goto err_up_io; + } + /* create a urb, and a buffer for it, and copy the data to the urb */ urb = usb_alloc_urb(0, GFP_KERNEL); if (!urb) { retval = -ENOMEM; - goto err_no_buf; + goto err_up_io; } buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, @@ -278,6 +298,7 @@ static ssize_t lcd_write(struct file *file, const char __user * user_buffer, the USB core will eventually free it entirely */ usb_free_urb(urb); + up_read(&dev->io_rwsem); exit: return count; error_unanchor: @@ -285,7 +306,8 @@ static ssize_t lcd_write(struct file *file, const char __user * user_buffer, error: usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); usb_free_urb(urb); -err_no_buf: +err_up_io: + up_read(&dev->io_rwsem); up(&dev->limit_sem); return retval; } @@ -325,6 +347,7 @@ static int lcd_probe(struct usb_interface *interface, kref_init(&dev->kref); sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); + init_rwsem(&dev->io_rwsem); init_usb_anchor(&dev->submitted); dev->udev = usb_get_dev(interface_to_usbdev(interface)); @@ -422,6 +445,12 @@ static void lcd_disconnect(struct usb_interface *interface) /* give back our minor */ usb_deregister_dev(interface, &lcd_class); + down_write(&dev->io_rwsem); + dev->disconnected = 1; + up_write(&dev->io_rwsem); + + usb_kill_anchored_urbs(&dev->submitted); + /* decrement our usage count */ kref_put(&dev->kref, lcd_delete); -- 2.23.0

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