Michael J. Ruhl bc5add0976 IB/hfi1: Close race condition on user context disable and close ... When disabling and removing a receive context, it is possible for an asynchronous event (i.e IRQ) to occur. Because of this, there is a race between cleaning up the context, and the context being used by the asynchronous event. cpu 0 (context cleanup) rc->ref_count-- (ref_count == 0) hfi1_rcd_free() cpu 1 (IRQ (with rcd index)) rcd_get_by_index() lock ref_count+++ <-- reference count race (WARNING) return rcd unlock cpu 0 hfi1_free_ctxtdata() <-- incorrect free location lock remove rcd from array unlock free rcd This race will cause the following WARNING trace: WARNING: CPU: 0 PID: 175027 at include/linux/kref.h:52 hfi1_rcd_get_by_index+0x84/0xa0 [hfi1] CPU: 0 PID: 175027 Comm: IMB-MPI1 Kdump: loaded Tainted: G OE ------------ 3.10.0-957.el7.x86_64 #1 Hardware name: Intel Corporation S2600KP/S2600KP, BIOS SE5C610.86B.11.01.0076.C4.111920150602 11/19/2015 Call Trace: dump_stack+0x19/0x1b __warn+0xd8/0x100 warn_slowpath_null+0x1d/0x20 hfi1_rcd_get_by_index+0x84/0xa0 [hfi1] is_rcv_urgent_int+0x24/0x90 [hfi1] general_interrupt+0x1b6/0x210 [hfi1] __handle_irq_event_percpu+0x44/0x1c0 handle_irq_event_percpu+0x32/0x80 handle_irq_event+0x3c/0x60 handle_edge_irq+0x7f/0x150 handle_irq+0xe4/0x1a0 do_IRQ+0x4d/0xf0 common_interrupt+0x162/0x162 The race can also lead to a use after free which could be similar to: general protection fault: 0000 1 SMP CPU: 71 PID: 177147 Comm: IMB-MPI1 Kdump: loaded Tainted: G W OE ------------ 3.10.0-957.el7.x86_64 #1 Hardware name: Intel Corporation S2600KP/S2600KP, BIOS SE5C610.86B.11.01.0076.C4.111920150602 11/19/2015 task: ffff9962a8098000 ti: ffff99717a508000 task.ti: ffff99717a508000 __kmalloc+0x94/0x230 Call Trace: ? hfi1_user_sdma_process_request+0x9c8/0x1250 [hfi1] hfi1_user_sdma_process_request+0x9c8/0x1250 [hfi1] hfi1_aio_write+0xba/0x110 [hfi1] do_sync_readv_writev+0x7b/0xd0 do_readv_writev+0xce/0x260 ? handle_mm_fault+0x39d/0x9b0 ? pick_next_task_fair+0x5f/0x1b0 ? sched_clock_cpu+0x85/0xc0 ? __schedule+0x13a/0x890 vfs_writev+0x35/0x60 SyS_writev+0x7f/0x110 system_call_fastpath+0x22/0x27 Use the appropriate kref API to verify access. Reorder context cleanup to ensure context removal before cleanup occurs correctly. Cc: stable@vger.kernel.org # v4.14.0+ Fixes: f683c80ca6 ("IB/hfi1: Resolve kernel panics by reference counting receive contexts") Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>		2019-03-06 14:47:09 -04:00
..
core	RDMA/umem: Revert broken 'off by one' fix	2019-03-06 14:42:37 -04:00
hw	IB/hfi1: Close race condition on user context disable and close	2019-03-06 14:47:09 -04:00
sw	IB/rdmavt: Fix concurrency panics in QP post_send and modify to error	2019-03-04 15:47:23 -04:00
ulp	IB/iser: Fix dma_nents type definition	2019-03-04 15:40:25 -04:00
Kconfig	IB/{core,uverbs}: Move ib_umem_xxx functions from ib_core to ib_uverbs	2019-01-10 17:06:44 -07:00
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