linux.git/drivers/net/netconsole.c, branch v6.12.80

net: netconsole: fix wrong warning

2024-10-10T02:42:43+00:00

A warning is triggered when there is insufficient space in the buffer
for userdata. However, this is not an issue since userdata will be sent
in the next iteration.

Current warning message:

    ------------[ cut here ]------------
     WARNING: CPU: 13 PID: 3013042 at drivers/net/netconsole.c:1122 write_ext_msg+0x3b6/0x3d0
      ? write_ext_msg+0x3b6/0x3d0
      console_flush_all+0x1e9/0x330

The code incorrectly issues a warning when this_chunk is zero, which is
a valid scenario. The warning should only be triggered when this_chunk
is negative.

Fixes: 1ec9daf95093 ("net: netconsole: append userdata to fragmented netconsole messages")
Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20241008094325.896208-1-leitao@debian.org
Signed-off-by: Jakub Kicinski

net: netconsole: Populate dynamic entry even if netpoll fails

2024-08-26T16:25:44+00:00

Currently, netconsole discards targets that fail during initialization,
causing two issues:

1) Inconsistency between target list and configfs entries
  * user pass cmdline0, cmdline1. If cmdline0 fails, then cmdline1
    becomes cmdline0 in configfs.

2) Inability to manage failed targets from userspace
  * If user pass a target that fails with netpoll (interface not loaded at
    netcons initialization time, such as interface is a module), then
    the target will not exist in the configfs, so, user cannot re-enable
    or modify it from userspace.

Failed targets are now added to the target list and configfs, but
remain disabled until manually enabled or reconfigured. This change does
not change the behaviour if CONFIG_NETCONSOLE_DYNAMIC is not set.

CC: Aijay Adams 
Signed-off-by: Breno Leitao 
Link: https://patch.msgid.link/20240822111051.179850-3-leitao@debian.org
Signed-off-by: Jakub Kicinski

net: netconsole: Constify struct config_item_type

2024-08-14T02:12:14+00:00

'struct config_item_type' is not modified in this driver.

This structure is only used with config_group_init_type_name() which takes
a const struct config_item_type* as a 3rd argument.

This also makes things consistent with 'netconsole_target_type' witch is
already const.

Constifying this structure moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  33007	   3952	   1312	  38271	   957f	drivers/net/netconsole.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  33071	   3888	   1312	  38271	   957f	drivers/net/netconsole.o

Signed-off-by: Christophe JAILLET 
Reviewed-by: Breno Leitao 
Link: https://patch.msgid.link/9c205b2b4bdb09fc9e9d2cb2f2936ec053da1b1b.1723325900.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski

net: netconsole: Defer netpoll cleanup to avoid lock release during list traversal

2024-08-13T08:58:58+00:00

Current issue:
- The `target_list_lock` spinlock is held while iterating over
  target_list() entries.
- Mid-loop, the lock is released to call __netpoll_cleanup(), then
  reacquired.
- This practice compromises the protection provided by
  `target_list_lock`.

Reason for current design:
1. __netpoll_cleanup() may sleep, incompatible with holding a spinlock.
2. target_list_lock must be a spinlock because write_msg() cannot sleep.
   (See commit b5427c27173e ("[NET] netconsole: Support multiple logging
    targets"))

Defer the cleanup of the netpoll structure to outside the
target_list_lock() protected area. Create another list
(target_cleanup_list) to hold the entries that need to be cleaned up,
and clean them using a mutex (target_cleanup_list_lock).

Signed-off-by: Breno Leitao 
Signed-off-by: Paolo Abeni

net: netconsole: Unify Function Return Paths

2024-08-13T08:58:58+00:00

The return flow in netconsole's dynamic functions is currently
inconsistent. This patch aims to streamline and standardize the process
by ensuring that the mutex is unlocked before returning the ret value.

Additionally, this update includes a minor functional change where
certain strnlen() operations are performed with the
dynamic_netconsole_mutex locked. This adjustment is not anticipated to
cause any issues, however, it is crucial to document this change for
clarity.

Signed-off-by: Breno Leitao 
Signed-off-by: Paolo Abeni

net: netconsole: Standardize variable naming

2024-08-13T08:58:58+00:00

Update variable names from err to ret in cases where the variable may
return non-error values.

This change facilitates a forthcoming patch that relies on ret being
used consistently to handle return values, regardless of whether they
indicate an error or not.

Signed-off-by: Breno Leitao 
Signed-off-by: Paolo Abeni

net: netconsole: Correct mismatched return types

2024-08-13T08:58:58+00:00

netconsole incorrectly mixes int and ssize_t types by using int for
return variables in functions that should return ssize_t.

This is fixed by updating the return variables to the appropriate
ssize_t type, ensuring consistency across the function definitions.

Signed-off-by: Breno Leitao 
Signed-off-by: Paolo Abeni

net: netconsole: Fix MODULE_AUTHOR format

2024-08-05T12:48:48+00:00

Update the MODULE_AUTHOR for netconsole, according to the format, as
stated in module.h:

	use "Name " or just "Name"

Suggested-by: Stephen Hemminger 
Signed-off-by: Breno Leitao 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-07-15T20:19:17+00:00

Merge in late fixes to prepare for the 6.11 net-next PR.

Conflicts:
  93c3a96c301f ("net: pse-pd: Do not return EOPNOSUPP if config is null")
  4cddb0f15ea9 ("net: ethtool: pse-pd: Fix possible null-deref")
  30d7b6727724 ("net: ethtool: Add new power limit get and set features")
https://lore.kernel.org/20240715123204.623520bb@canb.auug.org.au/

Signed-off-by: Jakub Kicinski

net: netconsole: Disable target before netpoll cleanup

2024-07-14T14:38:44+00:00

Currently, netconsole cleans up the netpoll structure before disabling
the target. This approach can lead to race conditions, as message
senders (write_ext_msg() and write_msg()) check if the target is
enabled before using netpoll. The sender can validate that the target is
enabled, but, the netpoll might be de-allocated already, causing
undesired behaviours.

This patch reverses the order of operations:
1. Disable the target
2. Clean up the netpoll structure

This change eliminates the potential race condition, ensuring that
no messages are sent through a partially cleaned-up netpoll structure.

Fixes: 2382b15bcc39 ("netconsole: take care of NETDEV_UNREGISTER event")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240712143415.1141039-1-leitao@debian.org
Signed-off-by: Jakub Kicinski