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[ Upstream commitd546b67cda] spin_lock/unlock was used instead of spin_un/lock_irq in a procedure used in process space, on a spinlock which can be grabbed in an interrupt. This caused the stack trace below to be displayed (on kernel 4.17.0-rc1 compiled with Lock Debugging enabled): [ 154.661474] WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected [ 154.668909] 4.17.0-rc1-rdma_rc_mlx+ #3 Tainted: G I [ 154.675856] ----------------------------------------------------- [ 154.682706] modprobe/10159 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 154.690254] 00000000f3b0e495 (&(&qp_table->lock)->rlock){+.+.}, at: mlx4_qp_remove+0x20/0x50 [mlx4_core] [ 154.700927] and this task is already holding: [ 154.707461] 0000000094373b5d (&(&cq->lock)->rlock/1){....}, at: destroy_qp_common+0x111/0x560 [mlx4_ib] [ 154.718028] which would create a new lock dependency: [ 154.723705] (&(&cq->lock)->rlock/1){....} -> (&(&qp_table->lock)->rlock){+.+.} [ 154.731922] but this new dependency connects a SOFTIRQ-irq-safe lock: [ 154.740798] (&(&cq->lock)->rlock){..-.} [ 154.740800] ... which became SOFTIRQ-irq-safe at: [ 154.752163] _raw_spin_lock_irqsave+0x3e/0x50 [ 154.757163] mlx4_ib_poll_cq+0x36/0x900 [mlx4_ib] [ 154.762554] ipoib_tx_poll+0x4a/0xf0 [ib_ipoib] ... to a SOFTIRQ-irq-unsafe lock: [ 154.815603] (&(&qp_table->lock)->rlock){+.+.} [ 154.815604] ... which became SOFTIRQ-irq-unsafe at: [ 154.827718] ... [ 154.827720] _raw_spin_lock+0x35/0x50 [ 154.833912] mlx4_qp_lookup+0x1e/0x50 [mlx4_core] [ 154.839302] mlx4_flow_attach+0x3f/0x3d0 [mlx4_core] Since mlx4_qp_lookup() is called only in process space, we can simply replace the spin_un/lock calls with spin_un/lock_irq calls. Fixes:6dc06c08be("net/mlx4: Fix the check in attaching steering rules") Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.