From 3f6c02fa712bd453871877fe1d1969625617471e Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Fri, 20 Jan 2023 17:03:32 +0100 Subject: serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler Requesting an interrupt with IRQF_ONESHOT will run the primary handler in the hard-IRQ context even in the force-threaded mode. The force-threaded mode is used by PREEMPT_RT in order to avoid acquiring sleeping locks (spinlock_t) in hard-IRQ context. This combination makes it impossible and leads to "sleeping while atomic" warnings. Use one interrupt handler for both handlers (primary and secondary) and drop the IRQF_ONESHOT flag which is not needed. Fixes: e359b4411c283 ("serial: stm32: fix threaded interrupt handling") Reviewed-by: Sebastian Andrzej Siewior Tested-by: Valentin Caron # V3 Signed-off-by: Marek Vasut Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230120160332.57930-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 33 +++++---------------------------- 1 file changed, 5 insertions(+), 28 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index a1490033aa16..409e91d6829a 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -797,25 +797,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) spin_unlock(&port->lock); } - if (stm32_usart_rx_dma_enabled(port)) - return IRQ_WAKE_THREAD; - else - return IRQ_HANDLED; -} - -static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) -{ - struct uart_port *port = ptr; - struct tty_port *tport = &port->state->port; - struct stm32_port *stm32_port = to_stm32_port(port); - unsigned int size; - unsigned long flags; - /* Receiver timeout irq for DMA RX */ - if (!stm32_port->throttled) { - spin_lock_irqsave(&port->lock, flags); + if (stm32_usart_rx_dma_enabled(port) && !stm32_port->throttled) { + spin_lock(&port->lock); size = stm32_usart_receive_chars(port, false); - uart_unlock_and_check_sysrq_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); } @@ -1015,10 +1001,8 @@ static int stm32_usart_startup(struct uart_port *port) u32 val; int ret; - ret = request_threaded_irq(port->irq, stm32_usart_interrupt, - stm32_usart_threaded_interrupt, - IRQF_ONESHOT | IRQF_NO_SUSPEND, - name, port); + ret = request_irq(port->irq, stm32_usart_interrupt, + IRQF_NO_SUSPEND, name, port); if (ret) return ret; @@ -1601,13 +1585,6 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, struct dma_slave_config config; int ret; - /* - * Using DMA and threaded handler for the console could lead to - * deadlocks. - */ - if (uart_console(port)) - return -ENODEV; - stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L, &stm32port->rx_dma_buf, GFP_KERNEL); -- cgit v1.2.3-58-ga151 From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ Tested-by: Gilles BULOZ Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dma.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags); -- cgit v1.2.3-58-ga151 From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ Tested-by: Gilles BULOZ Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dma.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); } -- cgit v1.2.3-58-ga151 From 226fae124b2dac217ea5436060d623ff3385bc34 Mon Sep 17 00:00:00 2001 From: George Kennedy Date: Tue, 24 Jan 2023 11:16:54 -0500 Subject: vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF After a call to console_unlock() in vcs_read() the vc_data struct can be freed by vc_deallocate(). Because of that, the struct vc_data pointer load must be done at the top of while loop in vcs_read() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537 CPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1 Hardware name: Red Hat KVM, BIOS 1.15.0-2.module Call Trace: __asan_report_load4_noabort (mm/kasan/report_generic.c:350) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_read (drivers/tty/vt/vc_screen.c:415) vfs_read (fs/read_write.c:468 fs/read_write.c:450) ... Allocated by task 1191: ... kmalloc_trace (mm/slab_common.c:1069) vc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720 drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108) con_install (drivers/tty/vt/vt.c:3383) tty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413 drivers/tty/tty_io.c:1390) tty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:883) vfs_open (fs/open.c:1014) ... Freed by task 1548: ... kfree (mm/slab_common.c:1021) vc_port_destruct (drivers/tty/vt/vt.c:1094) tty_port_destructor (drivers/tty/tty_port.c:296) tty_port_put (drivers/tty/tty_port.c:312) vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2)) vt_ioctl (drivers/tty/vt/vt_ioctl.c:903) tty_ioctl (drivers/tty/tty_io.c:2776) ... The buggy address belongs to the object at ffff888113747800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of 1024-byte region [ffff888113747800, ffff888113747c00) The buggy address belongs to the physical page: page:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113740 head:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0 anon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint Fixes: ac751efa6a0d ("console: rename acquire/release_console_sem() to console_lock/unlock()") Reported-by: syzkaller Suggested-by: Jiri Slaby Signed-off-by: George Kennedy Link: https://lore.kernel.org/r/1674577014-12374-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vc_screen.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c index 1850bacdb5b0..f566eb1839dc 100644 --- a/drivers/tty/vt/vc_screen.c +++ b/drivers/tty/vt/vc_screen.c @@ -386,10 +386,6 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) uni_mode = use_unicode(inode); attr = use_attributes(inode); - ret = -ENXIO; - vc = vcs_vc(inode, &viewed); - if (!vc) - goto unlock_out; ret = -EINVAL; if (pos < 0) @@ -407,6 +403,11 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) unsigned int this_round, skip = 0; int size; + ret = -ENXIO; + vc = vcs_vc(inode, &viewed); + if (!vc) + goto unlock_out; + /* Check whether we are above size each round, * as copy_to_user at the end of this loop * could sleep. -- cgit v1.2.3-58-ga151