From c1caadf9e890f2c27ff31ddd57c0b2527d94cf8e Mon Sep 17 00:00:00 2001 From: Thomas Lamprecht Date: Wed, 12 Apr 2023 13:22:23 +0200 Subject: [PATCH] backport "igb: revert rtnl_lock() that causes deadlock" Signed-off-by: Thomas Lamprecht --- ...evert-rtnl_lock-that-causes-deadlock.patch | 88 +++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 patches/kernel/0025-igb-revert-rtnl_lock-that-causes-deadlock.patch diff --git a/patches/kernel/0025-igb-revert-rtnl_lock-that-causes-deadlock.patch b/patches/kernel/0025-igb-revert-rtnl_lock-that-causes-deadlock.patch new file mode 100644 index 0000000..cb0e26f --- /dev/null +++ b/patches/kernel/0025-igb-revert-rtnl_lock-that-causes-deadlock.patch @@ -0,0 +1,88 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Lin Ma +Date: Tue, 7 Mar 2023 23:29:17 +0800 +Subject: [PATCH] igb: revert rtnl_lock() that causes deadlock + +commit 65f69851e44d71248b952a687e44759a7abb5016 upstream. + +The commit 6faee3d4ee8b ("igb: Add lock to avoid data race") adds +rtnl_lock to eliminate a false data race shown below + + (FREE from device detaching) | (USE from netdev core) +igb_remove | igb_ndo_get_vf_config + igb_disable_sriov | vf >= adapter->vfs_allocated_count? + kfree(adapter->vf_data) | + adapter->vfs_allocated_count = 0 | + | memcpy(... adapter->vf_data[vf] + +The above race will never happen and the extra rtnl_lock causes deadlock +below + +[ 141.420169] +[ 141.420672] __schedule+0x2dd/0x840 +[ 141.421427] schedule+0x50/0xc0 +[ 141.422041] schedule_preempt_disabled+0x11/0x20 +[ 141.422678] __mutex_lock.isra.13+0x431/0x6b0 +[ 141.423324] unregister_netdev+0xe/0x20 +[ 141.423578] igbvf_remove+0x45/0xe0 [igbvf] +[ 141.423791] pci_device_remove+0x36/0xb0 +[ 141.423990] device_release_driver_internal+0xc1/0x160 +[ 141.424270] pci_stop_bus_device+0x6d/0x90 +[ 141.424507] pci_stop_and_remove_bus_device+0xe/0x20 +[ 141.424789] pci_iov_remove_virtfn+0xba/0x120 +[ 141.425452] sriov_disable+0x2f/0xf0 +[ 141.425679] igb_disable_sriov+0x4e/0x100 [igb] +[ 141.426353] igb_remove+0xa0/0x130 [igb] +[ 141.426599] pci_device_remove+0x36/0xb0 +[ 141.426796] device_release_driver_internal+0xc1/0x160 +[ 141.427060] driver_detach+0x44/0x90 +[ 141.427253] bus_remove_driver+0x55/0xe0 +[ 141.427477] pci_unregister_driver+0x2a/0xa0 +[ 141.428296] __x64_sys_delete_module+0x141/0x2b0 +[ 141.429126] ? mntput_no_expire+0x4a/0x240 +[ 141.429363] ? syscall_trace_enter.isra.19+0x126/0x1a0 +[ 141.429653] do_syscall_64+0x5b/0x80 +[ 141.429847] ? exit_to_user_mode_prepare+0x14d/0x1c0 +[ 141.430109] ? syscall_exit_to_user_mode+0x12/0x30 +[ 141.430849] ? do_syscall_64+0x67/0x80 +[ 141.431083] ? syscall_exit_to_user_mode_prepare+0x183/0x1b0 +[ 141.431770] ? syscall_exit_to_user_mode+0x12/0x30 +[ 141.432482] ? do_syscall_64+0x67/0x80 +[ 141.432714] ? exc_page_fault+0x64/0x140 +[ 141.432911] entry_SYSCALL_64_after_hwframe+0x72/0xdc + +Since the igb_disable_sriov() will call pci_disable_sriov() before +releasing any resources, the netdev core will synchronize the cleanup to +avoid any races. This patch removes the useless rtnl_(un)lock to guarantee +correctness. + +CC: stable@vger.kernel.org +Fixes: 6faee3d4ee8b ("igb: Add lock to avoid data race") +Reported-by: Corinna Vinschen +Link: https://lore.kernel.org/intel-wired-lan/ZAcJvkEPqWeJHO2r@calimero.vinschen.de/ +Signed-off-by: Lin Ma +Tested-by: Corinna Vinschen +Reviewed-by: Jacob Keller +Reviewed-by: Simon Horman +Tested-by: Rafal Romanowski +Signed-off-by: Tony Nguyen +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Thomas Lamprecht +--- + drivers/net/ethernet/intel/igb/igb_main.c | 2 -- + 1 file changed, 2 deletions(-) + +diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c +index b246ff8b7c20..bff9649d8abd 100644 +--- a/drivers/net/ethernet/intel/igb/igb_main.c ++++ b/drivers/net/ethernet/intel/igb/igb_main.c +@@ -3820,9 +3820,7 @@ static void igb_remove(struct pci_dev *pdev) + igb_release_hw_control(adapter); + + #ifdef CONFIG_PCI_IOV +- rtnl_lock(); + igb_disable_sriov(pdev); +- rtnl_unlock(); + #endif + + unregister_netdev(netdev);