7442ddcedc
Recently nvme_dev.q_depth was changed from an int to u16 type. This falls over for the queue depth calculation in nvme_pci_enable(), where NVME_CAP_MQES(dev->ctrl.cap) + 1 may overflow as a u16, as NVME_CAP_MQES() is a 16b number also. That happens for me, and this is the result: root@ubuntu:/home/john# [148.272996] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 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=00000a27bf3c9000 [0000000000000010] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: nvme nvme_core CPU: 56 PID: 256 Comm: kworker/u195:0 Not tainted 5.8.0-next-20200812 #27 Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI RC0 - V1.16.01 03/15/2019 Workqueue: nvme-reset-wq nvme_reset_work [nvme] pstate: 80c00009 (Nzcv daif +PAN +UAO BTYPE=--) pc : __sg_alloc_table_from_pages+0xec/0x238 lr : __sg_alloc_table_from_pages+0xc8/0x238 sp : ffff800013ccbad0 x29: ffff800013ccbad0 x28: ffff0a27b3d380a8 x27: 0000000000000000 x26: 0000000000002dc2 x25: 0000000000000dc0 x24: 0000000000000000 x23: 0000000000000000 x22: ffff800013ccbbe8 x21: 0000000000000010 x20: 0000000000000000 x19: 00000000fffff000 x18: ffffffffffffffff x17: 00000000000000c0 x16: fffffe289eaf6380 x15: ffff800011b59948 x14: ffff002bc8fe98f8 x13: ff00000000000000 x12: ffff8000114ca000 x11: 0000000000000000 x10: ffffffffffffffff x9 : ffffffffffffffc0 x8 : ffff0a27b5f9b6a0 x7 : 0000000000000000 x6 : 0000000000000001 x5 : ffff0a27b5f9b680 x4 : 0000000000000000 x3 : ffff0a27b5f9b680 x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000000000 Call trace: __sg_alloc_table_from_pages+0xec/0x238 sg_alloc_table_from_pages+0x18/0x28 iommu_dma_alloc+0x474/0x678 dma_alloc_attrs+0xd8/0xf0 nvme_alloc_queue+0x114/0x160 [nvme] nvme_reset_work+0xb34/0x14b4 [nvme] process_one_work+0x1e8/0x360 worker_thread+0x44/0x478 kthread+0x150/0x158 ret_from_fork+0x10/0x34 Code: f94002c3 6b01017f 540007c2 11000486 (f8645aa5) ---[ end trace 89bb2b72d59bf925 ]--- Fix by making onto a u32. Also use u32 for nvme_dev.q_depth, as we assign this value from nvme_dev.q_depth, and nvme_dev.q_depth will possibly hold 65536 - this avoids the same crash as above. Fixes: 61f3b8963097 ("nvme-pci: use unsigned for io queue depth") Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.