mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-04 09:21:34 -04:00
62f99b62e5
Commit87fd125344("nvme-rdma: remove redundant reference between ib_device and tagset") caused a kernel panic when disconnecting from an inaccessible controller (disconnect during re-connection). -- nvme nvme0: Removing ctrl: NQN "testnqn1" nvme_rdma: nvme_rdma_exit_request: hctx 0 queue_idx 1 BUG: unable to handle kernel paging request at 0000000080000228 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... Call Trace: blk_mq_exit_hctx+0x5c/0xf0 blk_mq_exit_queue+0xd4/0x100 blk_cleanup_queue+0x9a/0xc0 nvme_rdma_destroy_io_queues+0x52/0x60 [nvme_rdma] nvme_rdma_shutdown_ctrl+0x3e/0x80 [nvme_rdma] nvme_do_delete_ctrl+0x53/0x80 [nvme_core] nvme_sysfs_delete+0x45/0x60 [nvme_core] kernfs_fop_write+0x105/0x180 vfs_write+0xad/0x1a0 ksys_write+0x5a/0xd0 do_syscall_64+0x55/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fa215417154 -- The reason for this crash is accessing an already freed ib_device for performing dma_unmap during exit_request commands. The root cause for that is that during re-connection all the queues are destroyed and re-created (and the ib_device is reference counted by the queues and freed as well) but the tagset stays alive and all the DMA mappings (that we perform in init_request) kept in the request context. The original commit fixed a different bug that was introduced during bonding (aka nic teaming) tests that for some scenarios change the underlying ib_device and caused memory leakage and possible segmentation fault. This commit is a complementary commit that also changes the wrong DMA mappings that were saved in the request context and making the request sqe dma mappings dynamic with the command lifetime (i.e. mapped in .queue_rq and unmapped in .complete). It also fixes the above crash of accessing freed ib_device during destruction of the tagset. Fixes:87fd125344("nvme-rdma: remove redundant reference between ib_device and tagset") Reported-by: Jim Harris <james.r.harris@intel.com> Suggested-by: Sagi Grimberg <sagi@grimberg.me> Tested-by: Jim Harris <james.r.harris@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
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.