From: Michael J. Ruhl michael.j.ruhl@intel.com
If the number of packets in a user sdma request does not match the actual iovectors being sent, sdma_cleanup can be called on an uninitialized request structure, resulting in a crash similar to this:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffffc0ae8bb7>] __sdma_txclean+0x57/0x1e0 [hfi1] PGD 8000001044f61067 PUD 1052706067 PMD 0 Oops: 0000 [#1] SMP CPU: 30 PID: 69912 Comm: upsm Kdump: loaded Tainted: G OE ------------ 3.10.0-862.el7.x86_64 #1 Hardware name: Intel Corporation S2600KPR/S2600KPR, BIOS SE5C610.86B.01.01.0019.101220160604 10/12/2016 task: ffff8b331c890000 ti: ffff8b2ed1f98000 task.ti: ffff8b2ed1f98000 RIP: 0010:[<ffffffffc0ae8bb7>] [<ffffffffc0ae8bb7>] __sdma_txclean+0x57/0x1e0 [hfi1] RSP: 0018:ffff8b2ed1f9bab0 EFLAGS: 00010286 RAX: 0000000000008b2b RBX: ffff8b2adf6e0000 RCX: 0000000000000000 RDX: 00000000000000a0 RSI: ffff8b2e9eedc540 RDI: ffff8b2adf6e0000 RBP: ffff8b2ed1f9bad8 R08: 0000000000000000 R09: ffffffffc0b04a06 R10: ffff8b331c890190 R11: ffffe6ed00bf1840 R12: ffff8b3315480000 R13: ffff8b33154800f0 R14: 00000000fffffff2 R15: ffff8b2e9eedc540 FS: 00007f035ac47740(0000) GS:ffff8b331e100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000c03fe6000 CR4: 00000000001607e0 Call Trace: [<ffffffffc0b0570d>] user_sdma_send_pkts+0xdcd/0x1990 [hfi1] [<ffffffff9fe75fb0>] ? gup_pud_range+0x140/0x290 [<ffffffffc0ad3105>] ? hfi1_mmu_rb_insert+0x155/0x1b0 [hfi1] [<ffffffffc0b0777b>] hfi1_user_sdma_process_request+0xc5b/0x11b0 [hfi1] [<ffffffffc0ac193a>] hfi1_aio_write+0xba/0x110 [hfi1] [<ffffffffa001a2bb>] do_sync_readv_writev+0x7b/0xd0 [<ffffffffa001bede>] do_readv_writev+0xce/0x260 [<ffffffffa022b089>] ? tty_ldisc_deref+0x19/0x20 [<ffffffffa02268c0>] ? n_tty_ioctl+0xe0/0xe0 [<ffffffffa001c105>] vfs_writev+0x35/0x60 [<ffffffffa001c2bf>] SyS_writev+0x7f/0x110 [<ffffffffa051f7d5>] system_call_fastpath+0x1c/0x21 Code: 06 49 c7 47 18 00 00 00 00 0f 87 89 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 2e 0f 1f 84 00 00 00 00 00 48 8b 4e 10 48 89 fb <48> 8b 51 08 49 89 d4 83 e2 0c 41 81 e4 00 e0 00 00 48 c1 ea 02 RIP [<ffffffffc0ae8bb7>] __sdma_txclean+0x57/0x1e0 [hfi1] RSP <ffff8b2ed1f9bab0> CR2: 0000000000000008
There are two exit points from user_sdma_send_pkts(). One (free_tx) merely frees the slab entry and one (free_txreq) cleans the sdma_txreq prior to freeing the slab entry. The free_txreq variation can only be called after one of the sdma_init*() variations has been called.
In the panic case, the slab entry had been allocated but not inited.
Fix the issue by exiting through free_tx thus avoiding sdma_clean().
Cc: stable@vger.kernel.org # 4.9.x+ Fixes: 7724105686e7 ("IB/hfi1: add driver files") Reviewed-by: Mike Marciniszyn mike.marciniszyn@intel.com Reviewed-by: Lukasz Odzioba lukasz.odzioa@intel.com Signed-off-by: Michael J. Ruhl michael.j.ruhl@intel.com Signed-off-by: Dennis Dalessandro dennis.dalessandro@intel.com --- drivers/infiniband/hw/hfi1/user_sdma.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index a3a7b33..5c88706 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -828,7 +828,7 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts) if (READ_ONCE(iovec->offset) == iovec->iov.iov_len) { if (++req->iov_idx == req->data_iovs) { ret = -EFAULT; - goto free_txreq; + goto free_tx; } iovec = &req->iovs[req->iov_idx]; WARN_ON(iovec->offset);