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bpf, docs: Add note about type convention #1301

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Pull request for series with
subject: bpf, docs: Add note about type convention
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465

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Master branch: 96f341a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Master branch: 96f341a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: b6d2079
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: b6d2079
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: b6d2079
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: e39e739
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: 97c4090
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: 3a07dcf
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: 3a07dcf
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: 3a07dcf
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: 3a07dcf
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: b54a0d4
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

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Upstream branch: d9095f9
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=689465
version: 1

@kernel-patches-bot kernel-patches-bot force-pushed the series/683109=>bpf-next branch 3 times, most recently from 3d7df0f to d6c49c4 Compare November 3, 2022 18:55
@kernel-patches-bot kernel-patches-bot force-pushed the series/683109=>bpf-next branch 3 times, most recently from 773aa96 to e6ba1ba Compare November 3, 2022 20:51
@kernel-patches-bot kernel-patches-bot force-pushed the series/683109=>bpf-next branch 15 times, most recently from 66565db to 708e313 Compare November 8, 2022 01:04
Kernel Patches Daemon and others added 5 commits November 7, 2022 17:15
adding ci files
7389cf2
@dthaler
bpf, docs: Add note about type convention
e3deb79 
Add note about type convention

Signed-off-by: Dave Thaler <dthaler@microsoft.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
@dthaler
bpf, docs: Fix modulo zero, division by zero, overflow, and underflow
011a643 
Fix modulo zero, division by zero, overflow, and underflow.
Also clarify how a negative immediate value is ued in unsigned division

Signed-off-by: Dave Thaler <dthaler@microsoft.com>
@dthaler
bpf, docs: Use consistent names for the same field
ef94bf7 
Use consistent names for the same field

Signed-off-by: Dave Thaler <dthaler@microsoft.com>
@dthaler
bpf, docs: Explain helper functions
20f8cc1 
Explain helper functions

Signed-off-by: Dave Thaler <dthaler@microsoft.com>
@danielocfb danielocfb closed this Nov 8, 2022
kernel-patches-daemon-bpf-rc bot pushed a commit that referenced this pull request Jul 1, 2025
@pcacjr
smb: client: fix potential deadlock when reconnecting channels
711741f 
Fix cifs_signal_cifsd_for_reconnect() to take the correct lock order
and prevent the following deadlock from happening

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc3-build2+ #1301 Tainted: G S      W
------------------------------------------------------
cifsd/6055 is trying to acquire lock:
ffff88810ad56038 (&tcp_ses->srv_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x134/0x200

but task is already holding lock:
ffff888119c64330 (&ret_buf->chan_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0xcf/0x200

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (&ret_buf->chan_lock){+.+.}-{3:3}:
       validate_chain+0x1cf/0x270
       __lock_acquire+0x60e/0x780
       lock_acquire.part.0+0xb4/0x1f0
       _raw_spin_lock+0x2f/0x40
       cifs_setup_session+0x81/0x4b0
       cifs_get_smb_ses+0x771/0x900
       cifs_mount_get_session+0x7e/0x170
       cifs_mount+0x92/0x2d0
       cifs_smb3_do_mount+0x161/0x460
       smb3_get_tree+0x55/0x90
       vfs_get_tree+0x46/0x180
       do_new_mount+0x1b0/0x2e0
       path_mount+0x6ee/0x740
       do_mount+0x98/0xe0
       __do_sys_mount+0x148/0x180
       do_syscall_64+0xa4/0x260
       entry_SYSCALL_64_after_hwframe+0x76/0x7e

-> #1 (&ret_buf->ses_lock){+.+.}-{3:3}:
       validate_chain+0x1cf/0x270
       __lock_acquire+0x60e/0x780
       lock_acquire.part.0+0xb4/0x1f0
       _raw_spin_lock+0x2f/0x40
       cifs_match_super+0x101/0x320
       sget+0xab/0x270
       cifs_smb3_do_mount+0x1e0/0x460
       smb3_get_tree+0x55/0x90
       vfs_get_tree+0x46/0x180
       do_new_mount+0x1b0/0x2e0
       path_mount+0x6ee/0x740
       do_mount+0x98/0xe0
       __do_sys_mount+0x148/0x180
       do_syscall_64+0xa4/0x260
       entry_SYSCALL_64_after_hwframe+0x76/0x7e

-> #0 (&tcp_ses->srv_lock){+.+.}-{3:3}:
       check_noncircular+0x95/0xc0
       check_prev_add+0x115/0x2f0
       validate_chain+0x1cf/0x270
       __lock_acquire+0x60e/0x780
       lock_acquire.part.0+0xb4/0x1f0
       _raw_spin_lock+0x2f/0x40
       cifs_signal_cifsd_for_reconnect+0x134/0x200
       __cifs_reconnect+0x8f/0x500
       cifs_handle_standard+0x112/0x280
       cifs_demultiplex_thread+0x64d/0xbc0
       kthread+0x2f7/0x310
       ret_from_fork+0x2a/0x230
       ret_from_fork_asm+0x1a/0x30

other info that might help us debug this:

Chain exists of:
  &tcp_ses->srv_lock --> &ret_buf->ses_lock --> &ret_buf->chan_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ret_buf->chan_lock);
                               lock(&ret_buf->ses_lock);
                               lock(&ret_buf->chan_lock);
  lock(&tcp_ses->srv_lock);

 *** DEADLOCK ***

3 locks held by cifsd/6055:
 #0: ffffffff857de398 (&cifs_tcp_ses_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x7b/0x200
 #1: ffff888119c64060 (&ret_buf->ses_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x9c/0x200
 #2: ffff888119c64330 (&ret_buf->chan_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0xcf/0x200

Cc: linux-cifs@vger.kernel.org
Reported-by: David Howells <dhowells@redhat.com>
Fixes: d7d7a66 ("cifs: avoid use of global locks for high contention data")
Reviewed-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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