4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Leon Romanovsky leonro@mellanox.com
commit 5c2e1c4f926856717f3fd31932e926dc3fe77ebd upstream.
There is no matching lock for this mutex. Git history suggests this is just a missed remnant from an earlier version of the function before this locking was moved into uverbs_free_xrcd.
Originally this lock was protecting the xrcd_table_delete()
===================================== WARNING: bad unlock balance detected! 4.15.0+ #87 Not tainted ------------------------------------- syzkaller223405/269 is trying to release lock (&uverbs_dev->xrcd_tree_mutex) at: [<00000000b8703372>] ib_uverbs_close_xrcd+0x195/0x1f0 but there are no more locks to release!
other info that might help us debug this: 1 lock held by syzkaller223405/269: #0: (&uverbs_dev->disassociate_srcu){....}, at: [<000000005af3b960>] ib_uverbs_write+0x265/0xef0
stack backtrace: CPU: 0 PID: 269 Comm: syzkaller223405 Not tainted 4.15.0+ #87 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 Call Trace: dump_stack+0xde/0x164 ? dma_virt_map_sg+0x22c/0x22c ? ib_uverbs_write+0x265/0xef0 ? console_unlock+0x502/0xbd0 ? ib_uverbs_close_xrcd+0x195/0x1f0 print_unlock_imbalance_bug+0x131/0x160 lock_release+0x59d/0x1100 ? ib_uverbs_close_xrcd+0x195/0x1f0 ? lock_acquire+0x440/0x440 ? lock_acquire+0x440/0x440 __mutex_unlock_slowpath+0x88/0x670 ? wait_for_completion+0x4c0/0x4c0 ? rdma_lookup_get_uobject+0x145/0x2f0 ib_uverbs_close_xrcd+0x195/0x1f0 ? ib_uverbs_open_xrcd+0xdd0/0xdd0 ib_uverbs_write+0x7f9/0xef0 ? cyc2ns_read_end+0x10/0x10 ? ib_uverbs_open_xrcd+0xdd0/0xdd0 ? uverbs_devnode+0x110/0x110 ? cyc2ns_read_end+0x10/0x10 ? cyc2ns_read_end+0x10/0x10 ? sched_clock_cpu+0x18/0x200 __vfs_write+0x10d/0x700 ? uverbs_devnode+0x110/0x110 ? kernel_read+0x170/0x170 ? __fget+0x358/0x5d0 ? security_file_permission+0x93/0x260 vfs_write+0x1b0/0x550 SyS_write+0xc7/0x1a0 ? SyS_read+0x1a0/0x1a0 ? trace_hardirqs_on_thunk+0x1a/0x1c entry_SYSCALL_64_fastpath+0x1e/0x8b RIP: 0033:0x4335c9
Cc: syzkaller syzkaller@googlegroups.com Cc: stable@vger.kernel.org # 4.11 Fixes: fd3c7904db6e ("IB/core: Change idr objects to use the new schema") Reported-by: Noa Osherovich noaos@mellanox.com Signed-off-by: Leon Romanovsky leonro@mellanox.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/infiniband/core/uverbs_cmd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -601,10 +601,8 @@ ssize_t ib_uverbs_close_xrcd(struct ib_u
uobj = uobj_get_write(uobj_get_type(xrcd), cmd.xrcd_handle, file->ucontext); - if (IS_ERR(uobj)) { - mutex_unlock(&file->device->xrcd_tree_mutex); + if (IS_ERR(uobj)) return PTR_ERR(uobj); - }
ret = uobj_remove_commit(uobj); return ret ?: in_len;