From bba676cc0b6122a74fa2e246f38a6b05c6f95b36 Mon Sep 17 00:00:00 2001 From: Dhananjay Phadke Date: Thu, 5 Aug 2021 14:49:05 -0700 Subject: i2c: iproc: fix race between client unreg and tasklet Similar NULL deref was originally fixed by graceful teardown sequence - https://lore.kernel.org/linux-i2c/1597106560-79693-1-git-send-email-dphadke@linux.microsoft.com After this, a tasklet was added to take care of FIFO full condition for large i2c transaction. https://lore.kernel.org/linux-arm-kernel/20201102035433.6774-1-rayagonda.kokatanur@broadcom.com/ This introduced regression, a new race condition between tasklet enabling interrupts and client unreg teardown sequence. Kill tasklet before unreg_slave() masks bits in IE_OFFSET. Updated teardown sequence - (1) disable_irq() (2) Kill tasklet (3) Mask event enable bits in control reg (4) Erase slave address (avoid further writes to rx fifo) (5) Flush tx and rx FIFOs (6) Clear pending event (interrupt) bits in status reg (7) Set client pointer to NULL (8) enable_irq() -- Unable to handle kernel read from unreadable memory at virtual address 0000000000000320 Mem abort info: ESR = 0x96000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=000000009212a000 [0000000000000320] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 96000004 [#1] SMP CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O Hardware name: Overlake (DT) pstate: 40400085 (nZcv daIf +PAN -UAO -TCO BTYPE=--) pc : bcm_iproc_i2c_slave_isr+0x2b8/0x8e4 lr : bcm_iproc_i2c_slave_isr+0x1c8/0x8e4 sp : ffff800010003e70 x29: ffff800010003e80 x28: ffffda017acdc000 x27: ffffda017b0ae000 x26: ffff800010004000 x25: ffff800010000000 x24: ffffda017af4a168 x23: 0000000000000073 x22: 0000000000000000 x21: 0000000001400000 x20: 0000000001000000 x19: ffff06f09583f880 x18: 00000000fa83b2da x17: 000000000000b67e x16: 0000000002edb2f3 x15: 00000000000002c7 x14: 00000000000002c7 x13: 0000000000000006 x12: 0000000000000033 x11: 0000000000000000 x10: 0000000001000000 x9 : 0000000003289312 x8 : 0000000003289311 x7 : 02d0cd03a303adbc x6 : 02d18e7f0a4dfc6c x5 : 02edb2f33f76ea68 x4 : 00000000fa83b2da x3 : ffffda017af43cd0 x2 : ffff800010003e74 x1 : 0000000001400000 x0 : 0000000000000000 Call trace: bcm_iproc_i2c_slave_isr+0x2b8/0x8e4 bcm_iproc_i2c_isr+0x178/0x290 __handle_irq_event_percpu+0xd0/0x200 handle_irq_event+0x60/0x1a0 handle_fasteoi_irq+0x130/0x220 __handle_domain_irq+0x8c/0xcc gic_handle_irq+0xc0/0x120 el1_irq+0xcc/0x180 finish_task_switch+0x100/0x1d8 __schedule+0x61c/0x7a0 schedule_idle+0x28/0x44 do_idle+0x254/0x28c cpu_startup_entry+0x28/0x2c rest_init+0xc4/0xd0 arch_call_rest_init+0x14/0x1c start_kernel+0x33c/0x3b8 Code: f9423260 910013e2 11000509 b9047a69 (f9419009) ---[ end trace 4781455b2a7bec15 ]--- Fixes: 4d658451c9d6 ("i2c: iproc: handle rx fifo full interrupt") Signed-off-by: Dhananjay Phadke Acked-by: Ray Jui Acked-by: Rayagonda Kokatanur Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-bcm-iproc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index cceaf69279a9..6304d1dd2dd6 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -1224,14 +1224,14 @@ static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) disable_irq(iproc_i2c->irq); + tasklet_kill(&iproc_i2c->slave_rx_tasklet); + /* disable all slave interrupts */ tmp = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); tmp &= ~(IE_S_ALL_INTERRUPT_MASK << IE_S_ALL_INTERRUPT_SHIFT); iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, tmp); - tasklet_kill(&iproc_i2c->slave_rx_tasklet); - /* Erase the slave address programmed */ tmp = iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET); tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); -- cgit v1.2.3 From 86ff25ed6cd8240d18df58930bd8848b19fce308 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 29 Jul 2021 16:35:32 +0200 Subject: i2c: dev: zero out array used for i2c reads from userspace If an i2c driver happens to not provide the full amount of data that a user asks for, it is possible that some uninitialized data could be sent to userspace. While all in-kernel drivers look to be safe, just be sure by initializing the buffer to zero before it is passed to the i2c driver so that any future drivers will not have this issue. Also properly copy the amount of data recvieved to the userspace buffer, as pointed out by Dan Carpenter. Reported-by: Eric Dumazet Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-dev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index cb64fe649390..77f576e51652 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -141,7 +141,7 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, if (count > 8192) count = 8192; - tmp = kmalloc(count, GFP_KERNEL); + tmp = kzalloc(count, GFP_KERNEL); if (tmp == NULL) return -ENOMEM; @@ -150,7 +150,8 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, ret = i2c_master_recv(client, tmp, count); if (ret >= 0) - ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret; + if (copy_to_user(buf, tmp, ret)) + ret = -EFAULT; kfree(tmp); return ret; } -- cgit v1.2.3 From 3f12cc4bb0a4d7b542af43b6f1b7175f13015629 Mon Sep 17 00:00:00 2001 From: Hu Haowen Date: Wed, 28 Jul 2021 23:53:46 +0800 Subject: Documentation: i2c: add i2c-sysfs into index Append i2c-sysfs to toctree in order to get rid of building warnings. Fixes: 31df7195b100 ("Documentation: i2c: Add doc for I2C sysfs") Signed-off-by: Hu Haowen Signed-off-by: Wolfram Sang --- Documentation/i2c/index.rst | 1 + 1 file changed, 1 insertion(+) diff --git a/Documentation/i2c/index.rst b/Documentation/i2c/index.rst index 8b76217e370a..6270f1fd7d4e 100644 --- a/Documentation/i2c/index.rst +++ b/Documentation/i2c/index.rst @@ -17,6 +17,7 @@ Introduction busses/index i2c-topology muxes/i2c-mux-gpio + i2c-sysfs Writing device drivers ====================== -- cgit v1.2.3