Daniel Borkmann f9dabe016b bpf: Undo off-by-one in interpreter tail call count limit ... The BPF interpreter as well as x86-64 BPF JIT were both in line by allowing up to 33 tail calls (however odd that number may be!). Recently, this was changed for the interpreter to reduce it down to 32 with the assumption that this should have been the actual limit "which is in line with the behavior of the x86 JITs" according to b61a28cf11 ("bpf: Fix off-by-one in tail call count limiting"). Paul recently reported: I'm a bit surprised by this because I had previously tested the tail call limit of several JIT compilers and found it to be 33 (i.e., allowing chains of up to 34 programs). I've just extended a test program I had to validate this again on the x86-64 JIT, and found a limit of 33 tail calls again [1]. Also note we had previously changed the RISC-V and MIPS JITs to allow up to 33 tail calls [2, 3], for consistency with other JITs and with the interpreter. We had decided to increase these two to 33 rather than decrease the other JITs to 32 for backward compatibility, though that probably doesn't matter much as I'd expect few people to actually use 33 tail calls. [1] ae78874829 [2] 96bc4432f5 ("bpf, riscv: Limit to 33 tail calls") [3] e49e6f6db0 ("bpf, mips: Limit to 33 tail calls") Therefore, revert b61a28cf11 to re-align interpreter to limit a maximum of 33 tail calls. While it is unlikely to hit the limit for the vast majority, programs in the wild could one way or another depend on this, so lets rather be a bit more conservative, and lets align the small remainder of JITs to 33. If needed in future, this limit could be slightly increased, but not decreased. Fixes: b61a28cf11 ("bpf: Fix off-by-one in tail call count limiting") Reported-by: Paul Chaignon <paul@cilium.io> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/CAO5pjwTWrC0_dzTbTHFPSqDwA56aVH+4KFGVqdq8=ASs0MqZGQ@mail.gmail.com		2021-08-19 18:33:37 +02:00
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bpf	bpf: Undo off-by-one in interpreter tail call count limit	2021-08-19 18:33:37 +02:00
cgroup	cgroup: rstat: fix A-A deadlock on 32bit around u64_stats_sync	2021-07-27 13:12:20 -10:00
configs	drivers/char: remove /dev/kmem for good	2021-05-07 00:26:34 -07:00
debug	kernel: debug: Fix unreachable code in gdb_serial_stub()	2021-07-12 11:03:35 -05:00
dma	dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable}	2021-07-16 11:30:26 +02:00
entry	tick/nohz: Only check for RCU deferred wakeup on user/guest entry when needed	2021-05-31 10:14:49 +02:00
events	bpf: Allow to specify user-provided bpf_cookie for BPF perf links	2021-08-17 00:45:07 +02:00
gcov	Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR	2021-06-22 11:07:18 -07:00
irq	irqchip fixes for 5.14, take #1	2021-07-09 15:35:13 +02:00
kcsan	Merge branch 'kcsan.2021.05.18a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu	2021-07-04 12:29:16 -07:00
livepatch	Livepatching changes for 5.13	2021-04-27 18:14:38 -07:00
locking	Locking fixes:	2021-07-11 11:06:09 -07:00
power	PM: hibernate: disable when there are active secretmem users	2021-07-08 11:48:21 -07:00
printk	printk changes for 5.14	2021-06-29 12:07:18 -07:00
rcu	rcu: Fix pr_info() formats and values in show_rcu_gp_kthreads()	2021-07-06 15:53:12 -07:00
sched	sched/rt: Fix double enqueue caused by rt_effective_prio	2021-08-04 15:16:31 +02:00
time	timers: Move clearing of base::timer_running under base:: Lock	2021-07-27 20:57:44 +02:00
trace	bpf: Add bpf_get_attach_cookie() BPF helper to access bpf_cookie value	2021-08-17 00:45:07 +02:00
.gitignore	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
acct.c	kernel/acct.c: use #elif instead of #end and #elif	2020-12-15 22:46:15 -08:00
async.c	kernel/async.c: remove async_unregister_domain()	2021-05-07 00:26:33 -07:00
audit.c	lsm: separate security_task_getsecid() into subjective and objective variants	2021-03-22 15:23:32 -04:00
audit.h	audit: remove trailing spaces and tabs	2021-06-10 20:59:05 -04:00
audit_fsnotify.c	audit_alloc_mark(): don't open-code ERR_CAST()	2021-02-23 10:25:27 -05:00
audit_tree.c	audit: Use list_move instead of list_del/list_add	2021-06-08 22:18:35 -04:00
audit_watch.c	fsnotify: generalize handle_inode_event()	2020-12-03 14:58:35 +01:00
auditfilter.c	lsm: separate security_task_getsecid() into subjective and objective variants	2021-03-22 15:23:32 -04:00
auditsc.c	audit: remove trailing spaces and tabs	2021-06-10 20:59:05 -04:00
backtracetest.c
bounds.c
capability.c	capability: handle idmapped mounts	2021-01-24 14:27:16 +01:00
cfi.c	add support for Clang CFI	2021-04-08 16:04:20 -07:00
compat.c
configs.c
context_tracking.c
cpu.c	A fix for the CPU hotplug and cpusets interaction:	2021-06-29 12:23:02 -07:00
cpu_pm.c
crash_core.c	kdump: use vmlinux_build_id to simplify	2021-07-08 11:48:22 -07:00
crash_dump.c
cred.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-06-28 20:39:26 -07:00
delayacct.c	delayacct: Add sysctl to enable at runtime	2021-05-12 11:43:25 +02:00
dma.c
exec_domain.c
exit.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-06-28 20:39:26 -07:00
extable.c
fail_function.c	fault-injection: handle EI_ETYPE_TRUE	2020-12-15 22:46:19 -08:00
fork.c	bpf: Add ambient BPF runtime context stored in current	2021-07-16 21:15:28 +02:00
freezer.c	sched: Add get_current_state()	2021-06-18 11:43:08 +02:00
futex.c	Locking changes for this cycle:	2021-06-28 11:45:29 -07:00
gen_kheaders.sh	kbuild: clean up ${quiet} checks in shell scripts	2021-05-27 04:01:50 +09:00
groups.c	groups: simplify struct group_info allocation	2021-02-26 09:41:03 -08:00
hung_task.c	Merge branch 'akpm' (patches from Andrew)	2021-07-02 12:08:10 -07:00
iomem.c
irq_work.c	irq_work: Make irq_work_queue() NMI-safe again	2021-06-10 10:00:08 +02:00
jump_label.c	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-05 10:46:20 +02:00
kallsyms.c	module: add printk formats to add module build ID to stacktraces	2021-07-08 11:48:22 -07:00
kcmp.c	Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2020-12-15 19:36:48 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt	sched/core: Disable CONFIG_SCHED_CORE by default	2021-06-28 22:43:05 +02:00
kcov.c	kernel: make kcov_common_handle consider the current context	2020-11-02 18:00:20 -08:00
kexec.c
kexec_core.c	kernel.h: split out panic and oops helpers	2021-07-01 11:06:04 -07:00
kexec_elf.c
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-07 00:26:32 -07:00
kexec_internal.h	kexec: move machine_kexec_post_load() to public interface	2021-02-22 12:33:26 +00:00
kheaders.c
kmod.c	modules: add CONFIG_MODPROBE_PATH	2021-05-07 00:26:33 -07:00
kprobes.c	Locking fixes:	2021-07-11 11:06:09 -07:00
ksysfs.c
kthread.c	Merge branch 'akpm' (patches from Andrew)	2021-06-29 17:29:11 -07:00
latencytop.c
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-02 00:43:35 +09:00
module-internal.h
module.c	module: add printk formats to add module build ID to stacktraces	2021-07-08 11:48:22 -07:00
module_signature.c	module: harden ELF info handling	2021-01-19 10:24:45 +01:00
module_signing.c	module: harden ELF info handling	2021-01-19 10:24:45 +01:00
notifier.c
nsproxy.c	fixes-v5.11	2020-12-14 16:40:27 -08:00
padata.c
panic.c	kernel.h: split out panic and oops helpers	2021-07-01 11:06:04 -07:00
params.c	Modules updates for v5.11	2020-12-17 13:01:31 -08:00
pid.c	Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2020-12-15 19:36:48 -08:00
pid_namespace.c	fixes-v5.11	2020-12-14 16:40:27 -08:00
profile.c	kernel: Initialize cpumask before parsing	2021-04-10 13:35:54 +02:00
ptrace.c	sched: Change task_struct::state	2021-06-18 11:43:09 +02:00
range.c	kernel.h: split out min()/max() et al. helpers	2020-10-16 11:11:19 -07:00
reboot.c	reboot: Add hardware protection power-off	2021-06-21 13:08:36 +01:00
regset.c
relay.c	relay: allow the use of const callback structs	2020-12-15 22:46:18 -08:00
resource.c	kernel/resource: fix return code check in __request_free_mem_region	2021-05-14 19:41:32 -07:00
resource_kunit.c	resource: provide meaningful MODULE_LICENSE() in test suite	2020-11-25 18:52:35 +01:00
rseq.c	rseq: Optimise rseq_get_rseq_cs() and clear_rseq_cs()	2021-04-14 18:04:09 +02:00
scftorture.c	scftorture: Avoid false-positive warnings in scftorture_invoker()	2021-07-06 12:37:55 -07:00
scs.c	scs: switch to vmapped shadow stacks	2020-12-01 10:30:28 +00:00
seccomp.c	seccomp: Fix setting loaded filter count during TSYNC	2021-08-11 11:48:28 -07:00
signal.c	Fix UCOUNT_RLIMIT_SIGPENDING counter leak	2021-07-08 11:43:24 -07:00
smp.c	smp: Fix smp_call_function_single_async prototype	2021-05-06 15:33:49 +02:00
smpboot.c	smpboot: fix duplicate and misplaced inlining directive	2021-07-25 11:06:37 -07:00
smpboot.h
softirq.c	sched: Introduce task_is_running()	2021-06-18 11:43:07 +02:00
stackleak.c
stacktrace.c
static_call.c	static_call: Fix static_call_text_reserved() vs __init	2021-07-05 10:46:33 +02:00
stop_machine.c	stop_machine: Add caller debug info to queue_stop_cpus_work	2021-03-23 16:01:58 +01:00
sys.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-06-28 20:39:26 -07:00
sys_ni.c	mm: introduce memfd_secret system call to create "secret" memory areas	2021-07-08 11:48:21 -07:00
sysctl-test.c	kernel/sysctl-test: Remove some casts which are no-longer required	2021-06-23 16:41:24 -06:00
sysctl.c	Merge branch 'akpm' (patches from Andrew)	2021-07-02 12:08:10 -07:00
task_work.c	kasan: record task_work_add() call stack	2021-04-30 11:20:42 -07:00
taskstats.c	treewide: rename nla_strlcpy to nla_strscpy.	2020-11-16 08:08:54 -08:00
test_kprobes.c
torture.c	torture: Replace torture_init_begin string with %s	2021-03-08 14:22:28 -08:00
tracepoint.c	tracepoint: Use rcu get state and cond sync for static call updates	2021-08-06 10:54:41 -04:00
tsacct.c
ucount.c	ucounts: add missing data type changes	2021-08-09 15:45:02 -05:00
uid16.c
uid16.h
umh.c	kernel/umh.c: fix some spelling mistakes	2021-05-07 00:26:34 -07:00
up.c	A set of locking related fixes and updates:	2021-05-09 13:07:03 -07:00
user-return-notifier.c
user.c	Reimplement RLIMIT_MEMLOCK on top of ucounts	2021-04-30 14:14:02 -05:00
user_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-06-28 20:39:26 -07:00
usermode_driver.c	Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2021-07-03 11:41:14 -07:00
utsname.c
utsname_sysctl.c
watch_queue.c	watch_queue: rectify kernel-doc for init_watch()	2021-01-26 11:16:34 +00:00
watchdog.c	kernel: watchdog: modify the explanation related to watchdog thread	2021-06-29 10:53:46 -07:00
watchdog_hld.c
workqueue.c	workqueue: fix UAF in pwq_unbound_release_workfn()	2021-07-21 06:42:31 -10:00
workqueue_internal.h