kernel/linux.git/include/linux, branch v4.14.289

cgroup: Use separate src/dst nodes when preloading css_sets for migration

2022-07-21T18:42:43+00:00

commit 07fd5b6cdf3cc30bfde8fe0f644771688be04447 upstream. Each cset (css_set) is pinned by its tasks. When we're moving tasks around across csets for a migration, we need to hold the source and destination csets to ensure that they don't go away while we're moving tasks about. This is done by linking cset->mg_preload_node on either the mgctx->preloaded_src_csets or mgctx->preloaded_dst_csets list. Using the same cset->mg_preload_node for both the src and dst lists was deemed okay as a cset can't be both the source and destination at the same time. Unfortunately, this overloading becomes problematic when multiple tasks are involved in a migration and some of them are identity noop migrations while others are actually moving across cgroups. For example, this can happen with the following sequence on cgroup1: #1> mkdir -p /sys/fs/cgroup/misc/a/b #2> echo $$ > /sys/fs/cgroup/misc/a/cgroup.procs #3> RUN_A_COMMAND_WHICH_CREATES_MULTIPLE_THREADS & #4> PID=$! #5> echo $PID > /sys/fs/cgroup/misc/a/b/tasks #6> echo $PID > /sys/fs/cgroup/misc/a/cgroup.procs the process including the group leader back into a. In this final migration, non-leader threads would be doing identity migration while the group leader is doing an actual one. After #3, let's say the whole process was in cset A, and that after #4, the leader moves to cset B. Then, during #6, the following happens: 1. cgroup_migrate_add_src() is called on B for the leader. 2. cgroup_migrate_add_src() is called on A for the other threads. 3. cgroup_migrate_prepare_dst() is called. It scans the src list. 4. It notices that B wants to migrate to A, so it tries to A to the dst list but realizes that its ->mg_preload_node is already busy. 5. and then it notices A wants to migrate to A as it's an identity migration, it culls it by list_del_init()'ing its ->mg_preload_node and putting references accordingly. 6. The rest of migration takes place with B on the src list but nothing on the dst list. This means that A isn't held while migration is in progress. If all tasks leave A before the migration finishes and the incoming task pins it, the cset will be destroyed leading to use-after-free. This is caused by overloading cset->mg_preload_node for both src and dst preload lists. We wanted to exclude the cset from the src list but ended up inadvertently excluding it from the dst list too. This patch fixes the issue by separating out cset->mg_preload_node into ->mg_src_preload_node and ->mg_dst_preload_node, so that the src and dst preloadings don't interfere with each other. Signed-off-by: Tejun Heo Reported-by: Mukesh Ojha Reported-by: shisiyuan Link: http://lkml.kernel.org/r/1654187688-27411-1-git-send-email-shisiyuan@xiaomi.com Link: https://www.spinics.net/lists/cgroups/msg33313.html Fixes: f817de98513d ("cgroup: prepare migration path for unified hierarchy") Cc: stable@vger.kernel.org # v3.16+ Signed-off-by: Greg Kroah-Hartman

net: Rename and export copy_skb_header

2022-07-07T15:31:18+00:00

commit 08303c189581c985e60f588ad92a041e46b6e307 upstream. [ jgross@suse.com: added as needed by XSA-403 mitigation ] copy_skb_header is renamed to skb_copy_header and exported. Exposing this function give more flexibility in copying SKBs. skb_copy and skb_copy_expand do not give enough control over which parts are copied. Signed-off-by: Ilya Lesokhin Signed-off-by: Boris Pismenny Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]

2022-07-02T14:18:11+00:00

commit 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc upstream. Since commit d1bcae833b32f1 ("ELF: Don't generate unused section symbols") [1], binutils (v2.36+) started dropping section symbols that it thought were unused. This isn't an issue in general, but with kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a separate .text.unlikely section and the section symbol ".text.unlikely" is being dropped. Due to this, recordmcount is unable to find a non-weak symbol in .text.unlikely to generate a relocation record against. Address this by dropping the weak attribute from these functions. Instead, follow the existing pattern of having architectures #define the name of the function they want to override in their headers. [1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1 [akpm@linux-foundation.org: arch/s390/include/asm/kexec.h needs linux/module.h] Link: https://lkml.kernel.org/r/20220519091237.676736-1-naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Michael Ellerman Signed-off-by: Naveen N. Rao Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

random: quiet urandom warning ratelimit suppression message

2022-07-02T14:18:08+00:00

commit c01d4d0a82b71857be7449380338bc53dde2da92 upstream. random.c ratelimits how much it warns about uninitialized urandom reads using __ratelimit(). When the RNG is finally initialized, it prints the number of missed messages due to ratelimiting. It has been this way since that functionality was introduced back in 2018. Recently, cc1e127bfa95 ("random: remove ratelimiting for in-kernel unseeded randomness") put a bit more stress on the urandom ratelimiting, which teased out a bug in the implementation. Specifically, when under pressure, __ratelimit() will print its own message and reset the count back to 0, making the final message at the end less useful. Secondly, it does so as a pr_warn(), which apparently is undesirable for people's CI. Fortunately, __ratelimit() has the RATELIMIT_MSG_ON_RELEASE flag exactly for this purpose, so we set the flag. Fixes: 4e00b339e264 ("random: rate limit unseeded randomness warnings") Cc: stable@vger.kernel.org Reported-by: Jon Hunter Reported-by: Ron Economos Tested-by: Ron Economos Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

vt: drop old FONT ioctls

2022-07-02T14:18:08+00:00

commit ff2047fb755d4415ec3c70ac799889371151796d upstream. Drop support for these ioctls: * PIO_FONT, PIO_FONTX * GIO_FONT, GIO_FONTX * PIO_FONTRESET As was demonstrated by commit 90bfdeef83f1 (tty: make FONTX ioctl use the tty pointer they were actually passed), these ioctls are not used from userspace, as: 1) they used to be broken (set up font on current console, not the open one) and racy (before the commit above) 2) KDFONTOP ioctl is used for years instead Note that PIO_FONTRESET is defunct on most systems as VGA_CONSOLE is set on them for ages. That turns on BROKEN_GRAPHICS_PROGRAMS which makes PIO_FONTRESET just return an error. We are removing KD_FONT_FLAG_OLD here as it was used only by these removed ioctls. kd.h header exists both in kernel and uapi headers, so we can remove the kernel one completely. Everyone includeing kd.h will now automatically get the uapi one. There are now unused definitions of the ioctl numbers and "struct consolefontdesc" in kd.h, but as it is a uapi header, I am not touching these. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210105120239.28031-8-jslaby@suse.cz Cc: guodaxing Signed-off-by: Greg Kroah-Hartman

random: mark bootloader randomness code as __init

2022-06-25T09:46:42+00:00

commit 39e0f991a62ed5efabd20711a7b6e7da92603170 upstream. add_bootloader_randomness() and the variables it touches are only used during __init and not after, so mark these as __init. At the same time, unexport this, since it's only called by other __init code that's built-in. Cc: stable@vger.kernel.org Fixes: 428826f5358c ("fdt: add support for rng-seed") Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: move randomize_page() into mm where it belongs

2022-06-25T09:46:40+00:00

commit 5ad7dd882e45d7fe432c32e896e2aaa0b21746ea upstream. randomize_page is an mm function. It is documented like one. It contains the history of one. It has the naming convention of one. It looks just like another very similar function in mm, randomize_stack_top(). And it has always been maintained and updated by mm people. There is no need for it to be in random.c. In the "which shape does not look like the other ones" test, pointing to randomize_page() is correct. So move randomize_page() into mm/util.c, right next to the similar randomize_stack_top() function. This commit contains no actual code changes. Cc: Andrew Morton Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: use proper return types on get_random_{int,long}_wait()

2022-06-25T09:46:40+00:00

commit 7c3a8a1db5e03d02cc0abb3357a84b8b326dfac3 upstream. Before these were returning signed values, but the API is intended to be used with unsigned values. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: remove extern from functions in header

2022-06-25T09:46:40+00:00

commit 7782cfeca7d420e8bb707613d4cfb0f7ff29bb3a upstream. Accoriding to the kernel style guide, having `extern` on functions in headers is old school and deprecated, and doesn't add anything. So remove them from random.h, and tidy up the file a little bit too. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: handle latent entropy and command line from random_init()

2022-06-25T09:46:40+00:00

commit 2f14062bb14b0fcfcc21e6dc7d5b5c0d25966164 upstream. Currently, start_kernel() adds latent entropy and the command line to the entropy bool *after* the RNG has been initialized, deferring when it's actually used by things like stack canaries until the next time the pool is seeded. This surely is not intended. Rather than splitting up which entropy gets added where and when between start_kernel() and random_init(), just do everything in random_init(), which should eliminate these kinds of bugs in the future. While we're at it, rename the awkwardly titled "rand_initialize()" to the more standard "random_init()" nomenclature. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman