github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity
9e5fcb003a
linux/kernel
History
Paul Chaignon 9e5fcb003a bpf: Avoid one round of bounds deduction 
In commit 5dbb19b16a ("bpf: Add third round of bounds deduction"), I
added a new round of bounds deduction because two rounds were not enough
to converge to a fixed point. This commit slightly refactor the bounds
deduction logic such that two rounds are enough.

In [1], Eduard noticed that after we improved the refinement logic, a
third call to the bounds deduction (__reg_deduce_bounds) was needed to
converge to a fixed point. More specifically, we needed this third call
to improve the s64 range using the s32 range. We added the third call
and postponed a more detailed analysis of the refinement logic.

I've been looking into this more recently. The register refinement
consists of the following calls.

    __update_reg_bounds();
    3 x __reg_deduce_bounds() {
        deduce_bounds_32_from_64();
        deduce_bounds_32_from_32();
        deduce_bounds_64_from_64();
        deduce_bounds_64_from_32();
    };
    __reg_bound_offset();
    __update_reg_bounds();

From this, we can observe that we first improve the 32bit ranges from
the 64bit ranges in deduce_bounds_32_from_64, then improve the 64bit
ranges on their own in deduce_bounds_64_from_64. Intuitively, if we
were to improve the 64bit ranges on their own *before* we use them to
improve the 32bit ranges, we may reach a fixed point earlier.

In a similar manner, using CBMC, Eduard found that it's best to improve
the 32bit ranges on their own *after* we've improve them using the 64bit
ranges. That is, running deduce_bounds_32_from_32 after
deduce_bounds_32_from_64.

These changes allow us to lose one call to __reg_deduce_bounds. Without
this reordering, the test "verifier_bounds/bounds deduction cross sign
boundary, negative overlap" fails when removing one call to
__reg_deduce_bounds. In some cases, this change can even improve
precision a little bit, as illustrated in the new selftest in the next
patch.

As expected, this change didn't have any impact on the number of
instructions processed when running it through the Cilium complexity
test suite [2].

Link: https://lore.kernel.org/bpf/aIKtSK9LjQXB8FLY@mail.gmail.com/ [1]
Link: https://pchaigno.github.io/test-verifier-complexity.html [2]
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Co-developed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/1b00d2749ec4c774c3ada84e265ac7fda72cfe56.1773401138.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-03-13 19:09:35 -07:00
..
bpf bpf: Avoid one round of bounds deduction 2026-03-13 19:09:35 -07:00
cgroup cgroup: Fixes for v7.0-rc2 2026-03-03 14:25:18 -08:00
configs Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-02-23 11:18:48 -08:00
debug treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
dma dma-mapping: avoid random addr value print out on error path 2026-02-23 08:26:54 +01:00
entry Merge branch 'core/entry' into sched/core 2026-01-30 15:40:05 +01:00
events perf: Fix __perf_event_overflow() vs perf_remove_from_context() race 2026-02-25 15:02:34 +01:00
futex Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
gcov Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
irq Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kcsan kcsan: test: Adjust "expect" allocation type for kmalloc_obj 2026-02-26 09:54:08 -08:00
livepatch Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
liveupdate liveupdate: luo_file: remember retrieve() status 2026-02-24 11:13:26 -08:00
locking Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
module module: Fix kernel panic when a symbol st_shndx is out of bounds 2026-02-23 19:37:28 +00:00
power Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
printk Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
rcu Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
sched Fix a DL scheduler bug that may corrupt internal metrics during 2026-03-07 17:07:13 -08:00
time Make clock_adjtime() syscall timex validation slightly more 2026-03-07 17:09:15 -08:00
trace bpf-fixes 2026-03-07 12:20:37 -08:00
unwind Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
.gitignore
acct.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
async.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_fsnotify.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_tree.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_watch.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit.h audit: fix comment misindentation in audit.h 2025-10-22 19:28:06 -04:00
auditfilter.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
auditsc.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
backtracetest.c
bounds.c x86/asm: Remove ANNOTATE_DATA_SPECIAL usage 2025-12-03 16:53:19 +01:00
capability.c
cfi.c
compat.c
configs.c
context_tracking.c context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}() 2026-01-01 16:39:46 +08:00
cpu_pm.c syscore: Pass context data to callbacks 2025-11-14 10:01:52 +01:00
cpu.c SPDX updates for 7.0-rc1 2026-02-17 09:46:03 -08:00
crash_core_test.c
crash_core.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crash_dump_dm_crypt.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crash_reserve.c crash: let architecture decide crash memory export to iomem_resource 2025-11-12 10:00:15 -08:00
cred.c cred: remove unused set_security_override_from_ctx() 2026-01-06 20:52:57 -05:00
delayacct.c delayacct: fix uapi timespec64 definition 2026-02-08 00:13:32 -08:00
dma.c
elfcorehdr.c
exec_domain.c
exit.c kthread: consolidate kthread exit paths to prevent use-after-free 2026-02-26 10:45:49 +01:00
exit.h
extable.c
fail_function.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
fork.c unshare: fix unshare_fs() handling 2026-02-18 14:04:51 +01:00
freezer.c freezer: Clarify that only cgroup1 freezer uses PM freezer 2025-10-30 20:10:27 +01:00
gen_kheaders.sh
groups.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
hung_task.c hung_task: add hung_task_sys_info sysctl to dump sys info on task-hung 2025-11-20 14:03:43 -08:00
iomem.c
irq_work.c
jump_label.c
kallsyms_internal.h kallsyms: Get rid of kallsyms relative base 2026-01-22 15:58:22 -07:00
kallsyms_selftest.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kallsyms_selftest.h
kallsyms.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.kexec liveupdate: kho: move to kernel/liveupdate 2025-11-27 14:24:33 -08:00
Kconfig.locks
Kconfig.preempt sched: Further restrict the preemption modes 2026-01-08 12:43:57 +01:00
kcov.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec_core.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec_elf.c
kexec_file.c kexec: derive purgatory entry from symbol 2026-01-31 16:16:07 -08:00
kexec_internal.h
kexec.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kheaders.c
kprobes.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kstack_erase.c sysctl: remove __user qualifier from stack_erasing_sysctl buffer argument 2025-11-27 15:44:53 +01:00
ksyms_common.c
ksysfs.c kexec: move sysfs entries to /sys/kernel/kexec 2025-11-27 14:24:42 -08:00
kthread.c kthread: consolidate kthread exit paths to prevent use-after-free 2026-02-26 10:45:49 +01:00
latencytop.c
Makefile kcov: Enable context analysis 2026-01-05 16:43:34 +01:00
module_signature.c
notifier.c
nscommon.c nsfs: tighten permission checks for ns iteration ioctls 2026-02-27 22:00:08 +01:00
nsproxy.c nsproxy: fix free_nsproxy() and simplify create_new_namespaces() 2025-11-14 13:10:38 +01:00
nstree.c nstree: tighten permission checks for listing 2026-02-27 22:00:11 +01:00
padata.c Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
panic.c panic: add panic_force_cpu= parameter to redirect panic to a specific CPU 2026-02-03 08:21:26 -08:00
params.c Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
pid_namespace.c pid: rely on common reference count behavior 2025-11-11 10:01:32 +01:00
pid_sysctl.h
pid.c Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers" 2026-02-10 11:39:30 +01:00
profile.c
ptrace.c rseq: Introduce struct rseq_data 2025-11-04 08:30:50 +01:00
range.c
reboot.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
regset.c
relay.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
resource_kunit.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
resource.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
rseq.c rseq: slice ext: Ensure rseq feature size differs from original rseq size 2026-02-23 11:19:19 +01:00
scftorture.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
scs.c scs: fix a wrong parameter in __scs_magic 2025-11-12 10:00:13 -08:00
seccomp.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
signal.c compiler-context-analysis: Remove __cond_lock() function-like helper 2026-01-05 16:43:33 +01:00
smp.c smp: Introduce a helper function to check for pending IPIs 2025-11-19 18:06:50 +01:00
smpboot.c
smpboot.h
softirq.c
stacktrace.c
static_call_inline.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
static_call.c
stop_machine.c
sys_ni.c rseq: Implement sys_rseq_slice_yield() 2026-01-22 11:11:17 +01:00
sys.c RISC-V updates for v7.0 2026-02-12 19:17:44 -08:00
sysctl-test.c
sysctl.c sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions 2026-01-06 11:27:10 +01:00
task_work.c task_work: Fix NMI race condition 2025-10-29 10:29:54 +01:00
taskstats.c
torture.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
tracepoint.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
tsacct.c tsacct: skip all kernel threads 2026-01-26 19:07:13 -08:00
ucount.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
uid16.c
uid16.h
umh.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
up.c
user_namespace.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
user-return-notifier.c
user.c ns: drop custom reference count initialization for initial namespaces 2025-11-11 10:01:32 +01:00
utsname_sysctl.c
utsname.c namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
vhost_task.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
vmcore_info.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
watch_queue.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
watchdog_buddy.c
watchdog_perf.c watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency 2026-02-08 00:13:35 -08:00
watchdog.c watchdog/softlockup: fix sample ring index wrap in need_counting_irqs() 2026-02-08 00:13:34 -08:00
workqueue_internal.h
workqueue.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00