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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Bart Van Assche <bvanassche@acm.org>,
	Jason Gunthorpe <jgg@mellanox.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-rdma@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 13/29] RDMA/iwcm: Fix a lock inversion issue
Date: Fri, 18 Oct 2019 18:09:04 -0400	[thread overview]
Message-ID: <20191018220920.10545-13-sashal@kernel.org> (raw)
In-Reply-To: <20191018220920.10545-1-sashal@kernel.org>

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit b66f31efbdad95ec274345721d99d1d835e6de01 ]

This patch fixes the lock inversion complaint:

============================================
WARNING: possible recursive locking detected
5.3.0-rc7-dbg+ #1 Not tainted
--------------------------------------------
kworker/u16:6/171 is trying to acquire lock:
00000000035c6e6c (&id_priv->handler_mutex){+.+.}, at: rdma_destroy_id+0x78/0x4a0 [rdma_cm]

but task is already holding lock:
00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&id_priv->handler_mutex);
  lock(&id_priv->handler_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by kworker/u16:6/171:
 #0: 00000000e2eaa773 ((wq_completion)iw_cm_wq){+.+.}, at: process_one_work+0x472/0xac0
 #1: 000000001efd357b ((work_completion)(&work->work)#3){+.+.}, at: process_one_work+0x476/0xac0
 #2: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm]

stack backtrace:
CPU: 3 PID: 171 Comm: kworker/u16:6 Not tainted 5.3.0-rc7-dbg+ #1
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: iw_cm_wq cm_work_handler [iw_cm]
Call Trace:
 dump_stack+0x8a/0xd6
 __lock_acquire.cold+0xe1/0x24d
 lock_acquire+0x106/0x240
 __mutex_lock+0x12e/0xcb0
 mutex_lock_nested+0x1f/0x30
 rdma_destroy_id+0x78/0x4a0 [rdma_cm]
 iw_conn_req_handler+0x5c9/0x680 [rdma_cm]
 cm_work_handler+0xe62/0x1100 [iw_cm]
 process_one_work+0x56d/0xac0
 worker_thread+0x7a/0x5d0
 kthread+0x1bc/0x210
 ret_from_fork+0x24/0x30

This is not a bug as there are actually two lock classes here.

Link: https://lore.kernel.org/r/20190930231707.48259-3-bvanassche@acm.org
Fixes: de910bd92137 ("RDMA/cma: Simplify locking needed for serialization of callbacks")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/core/cma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 85d4ef319c905..dcfbf326f45c9 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2119,9 +2119,10 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
 		conn_id->cm_id.iw = NULL;
 		cma_exch(conn_id, RDMA_CM_DESTROYING);
 		mutex_unlock(&conn_id->handler_mutex);
+		mutex_unlock(&listen_id->handler_mutex);
 		cma_deref_id(conn_id);
 		rdma_destroy_id(&conn_id->id);
-		goto out;
+		return ret;
 	}
 
 	mutex_unlock(&conn_id->handler_mutex);
-- 
2.20.1


  parent reply	other threads:[~2019-10-18 22:09 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-18 22:08 [PATCH AUTOSEL 4.9 01/29] sc16is7xx: Fix for "Unexpected interrupt: 8" Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 02/29] HID: i2c-hid: add Direkt-Tek DTLAPY133-1 to descriptor override Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 03/29] x86/cpu: Add Atom Tremont (Jacobsville) Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 04/29] HID: i2c-hid: Add Odys Winbook 13 to descriptor override Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 05/29] scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 06/29] usb: handle warm-reset port requests on hub resume Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 07/29] rtc: pcf8523: set xtal load capacitance from DT Sasha Levin
2019-10-18 22:08 ` [PATCH AUTOSEL 4.9 08/29] exec: load_script: Do not exec truncated interpreter path Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 09/29] iio: fix center temperature of bmc150-accel-core Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 10/29] perf map: Fix overlapped map handling Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 11/29] perf jevents: Fix period for Intel fixed counters Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 12/29] staging: rtl8188eu: fix null dereference when kzalloc fails Sasha Levin
2019-10-18 22:09 ` Sasha Levin [this message]
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 14/29] gpio: max77620: Use correct unit for debounce times Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 15/29] fs: cifs: mute -Wunused-const-variable message Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 16/29] serial: mctrl_gpio: Check for NULL pointer Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 17/29] efi/cper: Fix endianness of PCIe class code Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 18/29] efi/x86: Do not clean dummy variable in kexec path Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 19/29] ocfs2: clear zero in unaligned direct IO Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 20/29] fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry() Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 21/29] fs: ocfs2: fix a possible null-pointer dereference in ocfs2_write_end_nolock() Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 22/29] fs: ocfs2: fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc() Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 23/29] iio: adc: ad799x: fix probe error handling Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 24/29] iio: light: opt3001: fix mutex unlock race Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 25/29] MIPS: fw: sni: Fix out of bounds init of o32 stack Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 26/29] USB: usb-skeleton: fix use-after-free after driver unbind Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 27/29] NFSv4: Fix leak of clp->cl_acceptor string Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 28/29] s390/uaccess: avoid (false positive) compiler warnings Sasha Levin
2019-10-18 22:09 ` [PATCH AUTOSEL 4.9 29/29] tracing: Initialize iter->seq after zeroing in tracing_read_pipe() Sasha Levin

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