linux/kernel/ucount.c, branch v6.14

ucounts: move kfree() out of critical zone protected by ucounts_lock

2025-01-13T04:21:00Z

Although kfree is a non-sleep function, it is possible to enter a long chain of calls probabilistically, so it looks better to move kfree from alloc_ucounts() out of the critical zone of ucounts_lock. Link: https://lkml.kernel.org/r/1733458427-11794-1-git-send-email-mengensun@tencent.com Signed-off-by: MengEn Sun Reviewed-by: YueHong Wu Reviewed-by: Andrew Morton Cc: Andrei Vagin Cc: Joel Granados Cc: Thomas Weißschuh Signed-off-by: Andrew Morton

Merge tag 'sysctl-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

2024-11-23T04:36:11Z

Pull sysctl updates from Joel Granados: "sysctl ctl_table constification: - Constifying ctl_table structs prevents the modification of proc_handler function pointers. All ctl_table struct arguments are const qualified in the sysctl API in such a way that the ctl_table arrays being defined elsewhere and passed through sysctl can be constified one-by-one. We kick the constification off by qualifying user_table in kernel/ucount.c and expect all the ctl_tables to be constified in the coming releases. Misc fixes: - Adjust comments in two places to better reflect the code - Remove superfluous dput calls - Remove Luis from sysctl maintainership - Replace comments about holding a lock with calls to lockdep_assert_held" * tag 'sysctl-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: sysctl: Reduce dput(child) calls in proc_sys_fill_cache() sysctl: Reorganize kerneldoc parameter names ucounts: constify sysctl table user_table sysctl: update comments to new registration APIs MAINTAINERS: remove me from sysctl sysctl: Convert locking comments to lockdep assertions const_structs.checkpatch: add ctl_table sysctl: make internal ctl_tables const sysctl: allow registration of const struct ctl_table sysctl: move internal interfaces to const struct ctl_table bpf: Constify ctl_table argument of filter function

signal: restore the override_rlimit logic

2024-11-07T22:14:59Z

Prior to commit d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of signals. However now it's enforced unconditionally, even if override_rlimit is set. This behavior change caused production issues. For example, if the limit is reached and a process receives a SIGSEGV signal, sigqueue_alloc fails to allocate the necessary resources for the signal delivery, preventing the signal from being delivered with siginfo. This prevents the process from correctly identifying the fault address and handling the error. From the user-space perspective, applications are unaware that the limit has been reached and that the siginfo is effectively 'corrupted'. This can lead to unpredictable behavior and crashes, as we observed with java applications. Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip the comparison to max there if override_rlimit is set. This effectively restores the old behavior. Link: https://lkml.kernel.org/r/20241104195419.3962584-1-roman.gushchin@linux.dev Fixes: d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") Signed-off-by: Roman Gushchin Co-developed-by: Andrei Vagin Signed-off-by: Andrei Vagin Acked-by: Oleg Nesterov Acked-by: Alexey Gladkov Cc: Kees Cook Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton

ucounts: fix counter leak in inc_rlimit_get_ucounts()

2024-11-07T22:14:59Z

The inc_rlimit_get_ucounts() increments the specified rlimit counter and then checks its limit. If the value exceeds the limit, the function returns an error without decrementing the counter. Link: https://lkml.kernel.org/r/20241101191940.3211128-1-roman.gushchin@linux.dev Fixes: 15bc01effefe ("ucounts: Fix signal ucount refcounting") Signed-off-by: Andrei Vagin Co-developed-by: Roman Gushchin Signed-off-by: Roman Gushchin Tested-by: Roman Gushchin Acked-by: Alexey Gladkov Cc: Kees Cook Cc: Andrei Vagin Cc: "Eric W. Biederman" Cc: Alexey Gladkov Cc: Oleg Nesterov Cc: Signed-off-by: Andrew Morton

ucounts: constify sysctl table user_table

2024-10-23T13:28:40Z

The data of user_table is never modified, but only used as a template to create copies from. Signed-off-by: Thomas Weißschuh Signed-off-by: Joel Granados

Merge tag 'sysctl-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

2024-05-18T00:31:24Z

Pull sysctl updates from Joel Granados: - Remove sentinel elements from ctl_table structs in kernel/* Removing sentinels in ctl_table arrays reduces the build time size and runtime memory consumed by ~64 bytes per array. Removals for net/, io_uring/, mm/, ipc/ and security/ are set to go into mainline through their respective subsystems making the next release the most likely place where the final series that removes the check for proc_name == NULL will land. This adds to removals already in arch/, drivers/ and fs/. - Adjust ctl_table definitions and references to allow constification - Remove unused ctl_table function arguments - Move non-const elements from ctl_table to ctl_table_header - Make ctl_table pointers const in ctl_table_root structure Making the static ctl_table structs const will increase safety by keeping the pointers to proc_handler functions in .rodata. Though no ctl_tables where made const in this PR, the ground work for making that possible has started with these changes sent by Thomas Weißschuh. * tag 'sysctl-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: sysctl: drop now unnecessary out-of-bounds check sysctl: move sysctl type to ctl_table_header sysctl: drop sysctl_is_perm_empty_ctl_table sysctl: treewide: constify argument ctl_table_root::permissions(table) sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) bpf: Remove the now superfluous sentinel elements from ctl_table array delayacct: Remove the now superfluous sentinel elements from ctl_table array kprobes: Remove the now superfluous sentinel elements from ctl_table array printk: Remove the now superfluous sentinel elements from ctl_table array scheduler: Remove the now superfluous sentinel elements from ctl_table array seccomp: Remove the now superfluous sentinel elements from ctl_table array timekeeping: Remove the now superfluous sentinel elements from ctl_table array ftrace: Remove the now superfluous sentinel elements from ctl_table array umh: Remove the now superfluous sentinel elements from ctl_table array kernel misc: Remove the now superfluous sentinel elements from ctl_table array

sysctl: treewide: constify argument ctl_table_root::permissions(table)

2024-04-24T07:43:54Z

The permissions callback should not modify the ctl_table. Enforce this expectation via the typesystem. This is a step to put "struct ctl_table" into .rodata throughout the kernel. The patch was created with the following coccinelle script: @@ identifier func, head, ctl; @@ int func( struct ctl_table_header *head, - struct ctl_table *ctl) + const struct ctl_table *ctl) { ... } (insert_entry() from fs/proc/proc_sysctl.c is a false-positive) No additional occurrences of '.permissions =' were found after a tree-wide search for places missed by the conccinelle script. Reviewed-by: Joel Granados Signed-off-by: Thomas Weißschuh Signed-off-by: Joel Granados

kernel misc: Remove the now superfluous sentinel elements from ctl_table array

2024-04-24T07:43:53Z

This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove the sentinel from ctl_table arrays. Reduce by one the values used to compare the size of the adjusted arrays. Signed-off-by: Joel Granados

sysctl: treewide: constify ctl_table_header::ctl_table_arg

2024-04-22T07:56:31Z

To be able to constify instances of struct ctl_tables it is necessary to remove ways through which non-const versions are exposed from the sysctl core. One of these is the ctl_table_arg member of struct ctl_table_header. Constify this reference as a prerequisite for the full constification of struct ctl_table instances. No functional change. Signed-off-by: Thomas Weißschuh Reviewed-by: Kees Cook Signed-off-by: David S. Miller

sysctl: Add size to register_sysctl

2023-08-15T22:26:17Z

This commit adds table_size to register_sysctl in preparation for the removal of the sentinel elements in the ctl_table arrays (last empty markers). And though we do *not* remove any sentinels in this commit, we set things up by either passing the table_size explicitly or using ARRAY_SIZE on the ctl_table arrays. We replace the register_syctl function with a macro that will add the ARRAY_SIZE to the new register_sysctl_sz function. In this way the callers that are already using an array of ctl_table structs do not change. For the callers that pass a ctl_table array pointer, we pass the table_size to register_sysctl_sz instead of the macro. Signed-off-by: Joel Granados Suggested-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain