kernel/linux.git/include/linux/list.h, branch v6.12.80

list: leverage list_is_head() for list_entry_is_head()

2024-02-22T23:38:55+00:00

This is what list_is_head() exactly do. Link: https://lkml.kernel.org/r/20240208021423.15704-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang Cc: Andy Shevchenko Signed-off-by: Andrew Morton

list: add hlist_count_nodes()

2024-02-22T23:38:51+00:00

Add a generic hlist_count_nodes() function and use it in two drivers. This patch (of 3): Add a function to count nodes in a hlist. hlist_count_nodes() is similar to list_count_nodes(). Link: https://lkml.kernel.org/r/20240104164937.424320-1-pierre.gondois@arm.com Link: https://lkml.kernel.org/r/20240104164937.424320-2-pierre.gondois@arm.com Signed-off-by: Pierre Gondois Reviewed-by: Carlos Llamas Acked-by: Coly Li Acked-by: Marco Elver Reviewed-by: Andy Shevchenko Cc: Arve Hjønnevåg Cc: Christian Brauner Cc: Greg Kroah-Hartman Cc: Ingo Molnar Cc: Jani Nikula Cc: Joel Fernandes (Google) Cc: Kees Cook Cc: Kent Overstreet Cc: Martijn Coenen Cc: Suren Baghdasaryan Cc: Todd Kjos Signed-off-by: Andrew Morton

net: page_pool: record pools per netdev

2023-11-28T14:48:39+00:00

Link the page pools with netdevs. This needs to be netns compatible so we have two options. Either we record the pools per netns and have to worry about moving them as the netdev gets moved. Or we record them directly on the netdev so they move with the netdev without any extra work. Implement the latter option. Since pools may outlast netdev we need a place to store orphans. In time honored tradition use loopback for this purpose. Reviewed-by: Mina Almasry Reviewed-by: Eric Dumazet Acked-by: Jesper Dangaard Brouer Signed-off-by: Jakub Kicinski Signed-off-by: Paolo Abeni

: Introduce the list_for_each_reverse() method

2023-09-22T07:38:42+00:00

The list_head counterpart of list_for_each_entry_reverse() was missing, add it to complete the list handling APIs in . [ This new API is also relied on by a WIP scheduler patch, so this variant is not a theoretical possibility only. ] Signed-off-by: Ingo Molnar Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org

list: Introduce CONFIG_LIST_HARDENED

2023-08-15T21:57:25+00:00

Numerous production kernel configs (see [1, 2]) are choosing to enable CONFIG_DEBUG_LIST, which is also being recommended by KSPP for hardened configs [3]. The motivation behind this is that the option can be used as a security hardening feature (e.g. CVE-2019-2215 and CVE-2019-2025 are mitigated by the option [4]). The feature has never been designed with performance in mind, yet common list manipulation is happening across hot paths all over the kernel. Introduce CONFIG_LIST_HARDENED, which performs list pointer checking inline, and only upon list corruption calls the reporting slow path. To generate optimal machine code with CONFIG_LIST_HARDENED: 1. Elide checking for pointer values which upon dereference would result in an immediate access fault (i.e. minimal hardening checks). The trade-off is lower-quality error reports. 2. Use the __preserve_most function attribute (available with Clang, but not yet with GCC) to minimize the code footprint for calling the reporting slow path. As a result, function size of callers is reduced by avoiding saving registers before calling the rarely called reporting slow path. Note that all TUs in lib/Makefile already disable function tracing, including list_debug.c, and __preserve_most's implied notrace has no effect in this case. 3. Because the inline checks are a subset of the full set of checks in __list_*_valid_or_report(), always return false if the inline checks failed. This avoids redundant compare and conditional branch right after return from the slow path. As a side-effect of the checks being inline, if the compiler can prove some condition to always be true, it can completely elide some checks. Since DEBUG_LIST is functionally a superset of LIST_HARDENED, the Kconfig variables are changed to reflect that: DEBUG_LIST selects LIST_HARDENED, whereas LIST_HARDENED itself has no dependency on DEBUG_LIST. Running netperf with CONFIG_LIST_HARDENED (using a Clang compiler with "preserve_most") shows throughput improvements, in my case of ~7% on average (up to 20-30% on some test cases). Link: https://r.android.com/1266735 [1] Link: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/blob/main/config [2] Link: https://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project/Recommended_Settings [3] Link: https://googleprojectzero.blogspot.com/2019/11/bad-binder-android-in-wild-exploit.html [4] Signed-off-by: Marco Elver Link: https://lore.kernel.org/r/20230811151847.1594958-3-elver@google.com Signed-off-by: Kees Cook

list_debug: Introduce inline wrappers for debug checks

2023-08-15T21:57:24+00:00

Turn the list debug checking functions __list_*_valid() into inline functions that wrap the out-of-line functions. Care is taken to ensure the inline wrappers are always inlined, so that additional compiler instrumentation (such as sanitizers) does not result in redundant outlining. This change is preparation for performing checks in the inline wrappers. No functional change intended. Signed-off-by: Marco Elver Link: https://lore.kernel.org/r/20230811151847.1594958-2-elver@google.com Signed-off-by: Kees Cook

i915: Move list_count() to list.h as list_count_nodes() for broader use

2023-01-06T15:37:46+00:00

Some of the existing users, and definitely will be new ones, want to count existing nodes in the list. Provide a generic API for that by moving code from i915 to list.h. Reviewed-by: Lucas De Marchi Acked-by: Jani Nikula Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20221130134838.23805-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-05-27T18:22:03+00:00

Pull misc updates from Andrew Morton: "The non-MM patch queue for this merge window. Not a lot of material this cycle. Many singleton patches against various subsystems. Most notably some maintenance work in ocfs2 and initramfs" * tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits) kcov: update pos before writing pc in trace function ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock fs/ntfs: remove redundant variable idx fat: remove time truncations in vfat_create/vfat_mkdir fat: report creation time in statx fat: ignore ctime updates, and keep ctime identical to mtime in memory fat: split fat_truncate_time() into separate functions MAINTAINERS: add Muchun as a memcg reviewer proc/sysctl: make protected_* world readable ia64: mca: drop redundant spinlock initialization tty: fix deadlock caused by calling printk() under tty_port->lock relay: remove redundant assignment to pointer buf fs/ntfs3: validate BOOT sectors_per_clusters lib/string_helpers: fix not adding strarray to device's resource list kernel/crash_core.c: remove redundant check of ck_cmdline ELF, uapi: fixup ELF_ST_TYPE definition ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() ipc: update semtimedop() to use hrtimer ipc/sem: remove redundant assignments ...

rxrpc: Fix locking issue

2022-05-22T20:03:01+00:00

There's a locking issue with the per-netns list of calls in rxrpc. The pieces of code that add and remove a call from the list use write_lock() and the calls procfile uses read_lock() to access it. However, the timer callback function may trigger a removal by trying to queue a call for processing and finding that it's already queued - at which point it has a spare refcount that it has to do something with. Unfortunately, if it puts the call and this reduces the refcount to 0, the call will be removed from the list. Unfortunately, since the _bh variants of the locking functions aren't used, this can deadlock. ================================ WARNING: inconsistent lock state 5.18.0-rc3-build4+ #10 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. ksoftirqd/2/25 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff888107ac4038 (&rxnet->call_lock){+.?.}-{2:2}, at: rxrpc_put_call+0x103/0x14b {SOFTIRQ-ON-W} state was registered at: ... Possible unsafe locking scenario: CPU0 ---- lock(&rxnet->call_lock); lock(&rxnet->call_lock); *** DEADLOCK *** 1 lock held by ksoftirqd/2/25: #0: ffff8881008ffdb0 ((&call->timer)){+.-.}-{0:0}, at: call_timer_fn+0x5/0x23d Changes ======= ver #2) - Changed to using list_next_rcu() rather than rcu_dereference() directly. Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller

list: Add list_next_entry_circular() and list_prev_entry_circular()

2022-05-09T09:51:58+00:00

Add macros to get the next or previous entries and wraparound if needed. For example, calling list_next_entry_circular() on the last element should return the first element in the list. Signed-off-by: Ricardo Martinez Reviewed-by: Andy Shevchenko Signed-off-by: David S. Miller