[PATCH] acct(2): begin the deprecation of legacy BSD process accounting

[PATCH] acct(2): begin the deprecation of legacy BSD process accounting

[Jeff Layton]

As Christian points out [1], even though it's privileged, this interface
has a lot of footguns. There are better options these days (e.g. eBPF),
so it would be good to start discouraging its use and mark it as
deprecated.

[1]: https://lore.kernel.org/linux-fsdevel/20250212-giert-spannend-8893f1eaba7d@brauner/

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
I meant to send this months ago, but never got around to it. Let's at
least mark this as deprecated and see who complains. We could also
consider adding a pr_warn_once() that fires the first time someone calls
acct(2) if we want to kill this in a more near-term timeframe.
---
 init/Kconfig | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index fa79feb8fe57bb01d8ce8f35e33535709b57d452..160c1c4ef253593d62650cd5a53f3421bc9372d3 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -624,8 +624,9 @@ config SCHED_HW_PRESSURE
 	  arch_update_hw_pressure() and arch_scale_thermal_pressure().
 
 config BSD_PROCESS_ACCT
-	bool "BSD Process Accounting"
+	bool "BSD Process Accounting (DEPRECATED)"
 	depends on MULTIUSER
+	default n
 	help
 	  If you say Y here, a user level program will be able to instruct the
 	  kernel (via a special system call) to write process accounting
@@ -635,7 +636,9 @@ config BSD_PROCESS_ACCT
 	  command name, memory usage, controlling terminal etc. (the complete
 	  list is in the struct acct in <file:include/linux/acct.h>).  It is
 	  up to the user level program to do useful things with this
-	  information.  This is generally a good idea, so say Y.
+	  information.  This mechanism is antiquated and has significant
+	  scalability issues.  You probably want to use eBPF instead.  Say
+	  N unless you really need this.
 
 config BSD_PROCESS_ACCT_V3
 	bool "BSD Process Accounting version 3 file format"

---
base-commit: 7f98ab9da046865d57c102fd3ca9669a29845f67
change-id: 20260106-bsd-acct-c60be8e6ae62

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH] acct(2): begin the deprecation of legacy BSD process accounting

[Christian Brauner]

On Tue, 06 Jan 2026 09:38:22 -0500, Jeff Layton wrote:
> As Christian points out [1], even though it's privileged, this interface
> has a lot of footguns. There are better options these days (e.g. eBPF),
> so it would be good to start discouraging its use and mark it as
> deprecated.
> 
> [1]: https://lore.kernel.org/linux-fsdevel/20250212-giert-spannend-8893f1eaba7d@brauner/
> 
> [...]

Applied to the vfs-7.0.misc branch of the vfs/vfs.git tree.
Patches in the vfs-7.0.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.0.misc

[1/1] acct(2): begin the deprecation of legacy BSD process accounting
      https://git.kernel.org/vfs/vfs/c/24a4f4e1608f