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Abel Wu fac674d2bd bpf: Fix deadlock when freeing cgroup storage 
[ Upstream commit c78f4afbd9 ]

The following commit
bc235cdb42 ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
first introduced deadlock prevention for fentry/fexit programs attaching
on bpf_task_storage helpers. That commit also employed the logic in map
free path in its v6 version.

Later bpf_cgrp_storage was first introduced in
c4bcfb38a9 ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs")
which faces the same issue as bpf_task_storage, instead of its busy
counter, NULL was passed to bpf_local_storage_map_free() which opened
a window to cause deadlock:

	<TASK>
		(acquiring local_storage->lock)
	_raw_spin_lock_irqsave+0x3d/0x50
	bpf_local_storage_update+0xd1/0x460
	bpf_cgrp_storage_get+0x109/0x130
	bpf_prog_a4d4a370ba857314_cgrp_ptr+0x139/0x170
	? __bpf_prog_enter_recur+0x16/0x80
	bpf_trampoline_6442485186+0x43/0xa4
	cgroup_storage_ptr+0x9/0x20
		(holding local_storage->lock)
	bpf_selem_unlink_storage_nolock.constprop.0+0x135/0x160
	bpf_selem_unlink_storage+0x6f/0x110
	bpf_local_storage_map_free+0xa2/0x110
	bpf_map_free_deferred+0x5b/0x90
	process_one_work+0x17c/0x390
	worker_thread+0x251/0x360
	kthread+0xd2/0x100
	ret_from_fork+0x34/0x50
	ret_from_fork_asm+0x1a/0x30
	</TASK>

Progs:
 - A: SEC("fentry/cgroup_storage_ptr")
   - cgid (BPF_MAP_TYPE_HASH)
	Record the id of the cgroup the current task belonging
	to in this hash map, using the address of the cgroup
	as the map key.
   - cgrpa (BPF_MAP_TYPE_CGRP_STORAGE)
	If current task is a kworker, lookup the above hash
	map using function parameter @owner as the key to get
	its corresponding cgroup id which is then used to get
	a trusted pointer to the cgroup through
	bpf_cgroup_from_id(). This trusted pointer can then
	be passed to bpf_cgrp_storage_get() to finally trigger
	the deadlock issue.
 - B: SEC("tp_btf/sys_enter")
   - cgrpb (BPF_MAP_TYPE_CGRP_STORAGE)
	The only purpose of this prog is to fill Prog A's
	hash map by calling bpf_cgrp_storage_get() for as
	many userspace tasks as possible.

Steps to reproduce:
 - Run A;
 - while (true) { Run B; Destroy B; }

Fix this issue by passing its busy counter to the free procedure so
it can be properly incremented before storage/smap locking.

Fixes: c4bcfb38a9 ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs")
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20241221061018.37717-1-wuyun.abel@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-02-27 04:30:19 -08:00
arch powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC 2025-02-27 04:30:16 -08:00
block partitions: mac: fix handling of bogus partition table 2025-02-21 14:01:36 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix boot-up self-test race 2025-02-08 09:57:28 +01:00
Documentation strparser: Add read_sock callback 2025-02-27 04:30:19 -08:00
drivers net: axienet: Set mac_managed_pm 2025-02-27 04:30:18 -08:00
fs btrfs: fix double accounting race when extent_writepage_io() failed 2025-02-27 04:30:14 -08:00
include bpf: Fix wrong copied_seq calculation 2025-02-27 04:30:19 -08:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring/kbuf: reallocate buf lists on upgrade 2025-02-21 14:01:47 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel bpf: Fix deadlock when freeing cgroup storage 2025-02-27 04:30:19 -08:00
lib maple_tree: simplify split calculation 2025-02-17 10:05:42 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/compaction: fix UBSAN shift-out-of-bounds warning 2025-02-17 10:05:36 +01:00
net bpf: Disable non stream socket for strparser 2025-02-27 04:30:19 -08:00
rust rust: kbuild: add -fzero-init-padding-bits to bindgen_skip_cflags 2025-02-21 14:01:39 +01:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-02-08 09:57:11 +01:00
scripts kbuild: Use -fzero-init-padding-bits=all 2025-02-21 14:01:27 +01:00
security KEYS: trusted: dcp: fix improper sg use with CONFIG_VMAP_STACK=y 2025-02-17 10:05:09 +01:00
sound ALSA: seq: Drop UMP events when no UMP-conversion is set 2025-02-27 04:30:17 -08:00
tools selftests/bpf: Fix uprobe consumer test 2025-02-21 14:01:46 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update location of media main tree 2024-12-05 14:02:42 +01:00
Makefile Linux 6.12.16 2025-02-21 14:01:47 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.