possible circular locking in kernfs_remove_by_name_ns/devinet_ioctl linux 6.0-rc3
Francesco Dolcini
francesco.dolcini at toradex.com
Thu Sep 1 05:21:29 PDT 2022
Hello all,
I have this warning on linux 6.0-rc3, running on a ARM colibri-imx7.
[ 21.629186] ======================================================
[ 21.635418] WARNING: possible circular locking dependency detected
[ 21.641646] 6.0.0-rc3 #7 Not tainted
[ 21.645256] ------------------------------------------------------
[ 21.651480] connmand/542 is trying to acquire lock:
[ 21.656399] c2ce1d70 (kn->active#9){++++}-{0:0}, at: kernfs_remove_by_name_ns+0x50/0xa0
[ 21.664516]
but task is already holding lock:
[ 21.670394] c17af6e0 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0xc8/0x870
[ 21.677441]
which lock already depends on the new lock.
[ 21.685677]
the existing dependency chain (in reverse order) is:
[ 21.693230]
-> #2 (rtnl_mutex){+.+.}-{3:3}:
[ 21.698971] __mutex_lock+0x88/0x1110
[ 21.703208] mutex_lock_killable_nested+0x1c/0x28
[ 21.708487] register_netdev+0xc/0x34
[ 21.712721] gether_register_netdev+0x38/0xb0
[ 21.717654] rndis_bind+0x22c/0x39c
[ 21.721710] usb_add_function+0x7c/0x1e4
[ 21.726201] configfs_composite_bind+0x1bc/0x370
[ 21.731391] gadget_bind_driver+0x9c/0x204
[ 21.736059] really_probe+0xd8/0x3dc
[ 21.740201] __driver_probe_device+0x94/0x200
[ 21.745125] driver_probe_device+0x2c/0xd0
[ 21.749785] __driver_attach+0xc0/0x18c
[ 21.754184] bus_for_each_dev+0x74/0xc0
[ 21.758583] bus_add_driver+0x164/0x218
[ 21.762980] driver_register+0x74/0x10c
[ 21.767379] usb_gadget_register_driver_owner+0x40/0xd4
[ 21.773173] gadget_dev_desc_UDC_store+0xbc/0xf0
[ 21.778358] configfs_write_iter+0xac/0x110
[ 21.783110] vfs_write+0x2d4/0x46c
[ 21.787077] ksys_write+0x60/0xec
[ 21.790953] ret_fast_syscall+0x0/0x1c
[ 21.795265] 0xbeeb4b88
[ 21.798266]
-> #1 (udc_lock){+.+.}-{3:3}:
[ 21.803824] __mutex_lock+0x88/0x1110
[ 21.808054] mutex_lock_nested+0x1c/0x24
[ 21.812540] usb_udc_uevent+0x34/0xb0
[ 21.816763] dev_uevent+0x100/0x2dc
[ 21.820812] uevent_show+0x90/0x10c
[ 21.824860] dev_attr_show+0x18/0x48
[ 21.828999] sysfs_kf_seq_show+0x88/0x118
[ 21.833573] seq_read_iter+0x194/0x4bc
[ 21.837885] vfs_read+0x1a8/0x270
[ 21.841762] ksys_read+0x60/0xec
[ 21.845550] ret_fast_syscall+0x0/0x1c
[ 21.849860] 0xbea98840
[ 21.852857]
-> #0 (kn->active#9){++++}-{0:0}:
[ 21.858766] __lock_acquire+0x1550/0x23c0
[ 21.863344] lock_acquire+0x108/0x37c
[ 21.867570] __kernfs_remove+0x294/0x368
[ 21.872055] kernfs_remove_by_name_ns+0x50/0xa0
[ 21.877151] device_del+0x178/0x454
[ 21.881199] device_unregister+0x20/0x64
[ 21.885683] wakeup_source_unregister.part.0+0x20/0x3c
[ 21.891396] device_wakeup_disable+0x48/0x58
[ 21.896232] fec_enet_open+0x2ec/0x36c
[ 21.900547] __dev_open+0xec/0x180
[ 21.904512] __dev_change_flags+0x164/0x1d4
[ 21.909261] dev_change_flags+0x14/0x44
[ 21.913660] devinet_ioctl+0x6c8/0x870
[ 21.917971] inet_ioctl+0x1c4/0x2b8
[ 21.922019] sock_ioctl+0x458/0x4fc
[ 21.926072] sys_ioctl+0xf4/0xe04
[ 21.929948] ret_fast_syscall+0x0/0x1c
[ 21.934258] 0xbeeca960
[ 21.937256]
other info that might help us debug this:
[ 21.945318] Chain exists of:
kn->active#9 --> udc_lock --> rtnl_mutex
[ 21.954902] Possible unsafe locking scenario:
[ 21.960865] CPU0 CPU1
[ 21.965430] ---- ----
[ 21.969994] lock(rtnl_mutex);
[ 21.973174] lock(udc_lock);
[ 21.978709] lock(rtnl_mutex);
[ 21.984419] lock(kn->active#9);
[ 21.987779]
*** DEADLOCK ***
[ 21.993745] 1 lock held by connmand/542:
[ 21.997704] #0: c17af6e0 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0xc8/0x870
[ 22.005191]
stack backtrace:
[ 22.009587] CPU: 0 PID: 542 Comm: connmand Not tainted 6.0.0-rc3 #7
[ 22.015905] Hardware name: Freescale i.MX7 Dual (Device Tree)
[ 22.021703] unwind_backtrace from show_stack+0x10/0x14
[ 22.026985] show_stack from dump_stack_lvl+0x58/0x70
[ 22.032088] dump_stack_lvl from check_noncircular+0xf4/0x168
[ 22.037891] check_noncircular from check_prev_add+0xc4/0x15d8
[ 22.043783] check_prev_add from __lock_acquire+0x1550/0x23c0
[ 22.049587] __lock_acquire from lock_acquire+0x108/0x37c
[ 22.055041] lock_acquire from __kernfs_remove+0x294/0x368
[ 22.060582] __kernfs_remove from kernfs_remove_by_name_ns+0x50/0xa0
[ 22.066991] kernfs_remove_by_name_ns from device_del+0x178/0x454
[ 22.073141] device_del from device_unregister+0x20/0x64
[ 22.078501] device_unregister from wakeup_source_unregister.part.0+0x20/0x3c
[ 22.085700] wakeup_source_unregister.part.0 from device_wakeup_disable+0x48/0x58
[ 22.093253] device_wakeup_disable from fec_enet_open+0x2ec/0x36c
[ 22.099408] fec_enet_open from __dev_open+0xec/0x180
[ 22.104514] __dev_open from __dev_change_flags+0x164/0x1d4
[ 22.110141] __dev_change_flags from dev_change_flags+0x14/0x44
[ 22.116117] dev_change_flags from devinet_ioctl+0x6c8/0x870
[ 22.121830] devinet_ioctl from inet_ioctl+0x1c4/0x2b8
[ 22.127017] inet_ioctl from sock_ioctl+0x458/0x4fc
[ 22.131946] sock_ioctl from sys_ioctl+0xf4/0xe04
[ 22.136701] sys_ioctl from ret_fast_syscall+0x0/0x1c
[ 22.141802] Exception stack(0xf1269fa8 to 0xf1269ff0)
[ 22.146900] 9fa0: 00000000 beeca984 00000010 00008914 beeca984 beeca978
[ 22.155141] 9fc0: 00000000 beeca984 00000010 00000036 00000003 00001002 00000e94 beecab3c
[ 22.163380] 9fe0: 00000036 beeca960 b6b58089 b6ad1ae6
The kernel configuration used is based on imx_v6_v7_defconfig with the
following changes:
--- original 2022-09-01 14:13:12.334642373 +0200
+++ new 2022-09-01 14:12:46.799096809 +0200
@@ -1 +1 @@
-CONFIG_KERNEL_LZO=y
+CONFIG_KERNEL_LZ4=y
@@ -18,5 +17,0 @@
-CONFIG_SOC_IMX31=y
-CONFIG_SOC_IMX35=y
-CONFIG_SOC_IMX50=y
-CONFIG_SOC_IMX51=y
-CONFIG_SOC_IMX53=y
@@ -24,3 +18,0 @@
-CONFIG_SOC_IMX6SL=y
-CONFIG_SOC_IMX6SLL=y
-CONFIG_SOC_IMX6SX=y
@@ -29,2 +20,0 @@
-CONFIG_SOC_IMX7ULP=y
-CONFIG_SOC_VF610=y
@@ -36 +25,0 @@
-CONFIG_KEXEC=y
@@ -58,0 +48 @@
+# CONFIG_SWAP is not set
@@ -67,0 +58,2 @@
+CONFIG_CAN_FLEXCAN=y
+CONFIG_CAN_MCP251X=m
@@ -71,0 +64,2 @@
+CONFIG_BT_MRVL=m
+CONFIG_BT_MRVL_SDIO=m
@@ -101 +94,0 @@
-CONFIG_MTD_NAND_VF610_NFC=y
@@ -103 +95,0 @@
-CONFIG_MTD_SPI_NOR=y
@@ -121 +112,0 @@
-CONFIG_PATA_IMX=y
@@ -138 +128,0 @@
-CONFIG_CAN_FLEXCAN=y
@@ -200,0 +191 @@
+CONFIG_SPI_MEM=y
@@ -204,5 +195 @@
-CONFIG_SPI_FSL_DSPI=y
-CONFIG_PINCTRL_IMX8MM=y
-CONFIG_PINCTRL_IMX8MN=y
-CONFIG_PINCTRL_IMX8MP=y
-CONFIG_PINCTRL_IMX8MQ=y
+CONFIG_SPI_SPIDEV=y
@@ -240,0 +228 @@
+CONFIG_REGULATOR=y
@@ -252,3 +239,0 @@
-CONFIG_RC_CORE=y
-CONFIG_RC_DEVICES=y
-CONFIG_IR_GPIO_CIR=y
@@ -269 +253,0 @@
-CONFIG_DRM_MSM=y
@@ -273,0 +258 @@
+CONFIG_DRM_SIMPLE_BRIDGE=y
@@ -391,5 +376 @@
-CONFIG_CLK_IMX8MM=y
-CONFIG_CLK_IMX8MN=y
-CONFIG_CLK_IMX8MP=y
-CONFIG_CLK_IMX8MQ=y
-CONFIG_SOC_IMX8M=y
+CONFIG_EXTCON_USB_GPIO=y
@@ -410 +390,0 @@
-CONFIG_NVMEM_VF610_OCOTP=y
@@ -417 +397 @@
-CONFIG_EXT2_FS=y
+CONFIG_EXT2_FS=m
@@ -421 +401 @@
-CONFIG_EXT3_FS=y
+CONFIG_EXT3_FS=m
@@ -423,0 +404 @@
+CONFIG_EXT4_FS=y
@@ -428 +409 @@
-CONFIG_FUSE_FS=y
+CONFIG_FUSE_FS=m
@@ -434,0 +416 @@
+CONFIG_NTFS3_FS=m
@@ -436 +418 @@
-CONFIG_JFFS2_FS=y
+CONFIG_JFFS2_FS=m
@@ -457 +439,3 @@
-CONFIG_CMA_SIZE_MBYTES=64
+CONFIG_CMA_SIZE_MBYTES=256
+CONFIG_CMA_SIZE_PERCENTAGE=50
+CONFIG_CMA_SIZE_SEL_MIN=y
@@ -461,0 +446 @@
+CONFIG_DYNAMIC_DEBUG=y
I have not tried to bisect this yet, just probing if someone has already
some idea on this.
Francesco
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