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A mirror of the official Linux kernel repository just in case
d877d7275b
Move the code for parsing an XCOPY command from the context of the iSCSI receiver thread to the context of the XCOPY workqueue. Keep the simple XCOPY checks in the context of the iSCSI receiver thread. Move the code for allocating and freeing struct xcopy_op from the code that parses an XCOPY command to its caller. This patch fixes the following deadlock: ====================================================== [ INFO: possible circular locking dependency detected ] 4.10.0-rc7-dbg+ #1 Not tainted ------------------------------------------------------- rmdir/13321 is trying to acquire lock: (&sess->cmdsn_mutex){+.+.+.}, at: [<ffffffffa02cb47d>] iscsit_free_all_ooo_cmdsns+0x2d/0xb0 [iscsi_target_mod] but task is already holding lock: (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff811c6e20>] vfs_rmdir+0x50/0x140 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#14){++++++}: lock_acquire+0x71/0x90 down_write+0x3f/0x70 configfs_depend_item+0x3a/0xb0 [configfs] target_depend_item+0x13/0x20 [target_core_mod] target_xcopy_locate_se_dev_e4+0xdd/0x1a0 [target_core_mod] target_do_xcopy+0x34b/0x970 [target_core_mod] __target_execute_cmd+0x22/0xa0 [target_core_mod] target_execute_cmd+0x233/0x2c0 [target_core_mod] iscsit_execute_cmd+0x208/0x270 [iscsi_target_mod] iscsit_sequence_cmd+0x10b/0x190 [iscsi_target_mod] iscsit_get_rx_pdu+0x37d/0xcd0 [iscsi_target_mod] iscsi_target_rx_thread+0x6e/0xa0 [iscsi_target_mod] kthread+0x102/0x140 ret_from_fork+0x31/0x40 -> #0 (&sess->cmdsn_mutex){+.+.+.}: __lock_acquire+0x10e6/0x1260 lock_acquire+0x71/0x90 mutex_lock_nested+0x5f/0x670 iscsit_free_all_ooo_cmdsns+0x2d/0xb0 [iscsi_target_mod] iscsit_close_session+0xac/0x200 [iscsi_target_mod] lio_tpg_close_session+0x9f/0xb0 [iscsi_target_mod] target_shutdown_sessions+0xc3/0xd0 [target_core_mod] core_tpg_del_initiator_node_acl+0x91/0x140 [target_core_mod] target_fabric_nacl_base_release+0x20/0x30 [target_core_mod] config_item_release+0x5a/0xc0 [configfs] config_item_put+0x1d/0x1f [configfs] configfs_rmdir+0x1a6/0x300 [configfs] vfs_rmdir+0xb7/0x140 do_rmdir+0x1f4/0x200 SyS_rmdir+0x11/0x20 entry_SYSCALL_64_fastpath+0x23/0xc6 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#14); lock(&sess->cmdsn_mutex); lock(&sb->s_type->i_mutex_key#14); lock(&sess->cmdsn_mutex); *** DEADLOCK *** 3 locks held by rmdir/13321: #0: (sb_writers#10){.+.+.+}, at: [<ffffffff811e1aff>] mnt_want_write+0x1f/0x50 #1: (&default_group_class[depth - 1]#2/1){+.+.+.}, at: [<ffffffff811cc8ce>] do_rmdir+0x15e/0x200 #2: (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff811c6e20>] vfs_rmdir+0x50/0x140 stack backtrace: CPU: 2 PID: 13321 Comm: rmdir Not tainted 4.10.0-rc7-dbg+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 Call Trace: dump_stack+0x86/0xc3 print_circular_bug+0x1c7/0x220 __lock_acquire+0x10e6/0x1260 lock_acquire+0x71/0x90 mutex_lock_nested+0x5f/0x670 iscsit_free_all_ooo_cmdsns+0x2d/0xb0 [iscsi_target_mod] iscsit_close_session+0xac/0x200 [iscsi_target_mod] lio_tpg_close_session+0x9f/0xb0 [iscsi_target_mod] target_shutdown_sessions+0xc3/0xd0 [target_core_mod] core_tpg_del_initiator_node_acl+0x91/0x140 [target_core_mod] target_fabric_nacl_base_release+0x20/0x30 [target_core_mod] config_item_release+0x5a/0xc0 [configfs] config_item_put+0x1d/0x1f [configfs] configfs_rmdir+0x1a6/0x300 [configfs] vfs_rmdir+0xb7/0x140 do_rmdir+0x1f4/0x200 SyS_rmdir+0x11/0x20 entry_SYSCALL_64_fastpath+0x23/0xc6 Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Andy Grover <agrover@redhat.com> Cc: David Disseldorp <ddiss@suse.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.