Kumar Kartikeya Dwivedi aa42a7cb92 bpf: Detect IP == ksym.end as part of BPF program ... [ Upstream commit 66d9111f3517f85ef2af0337ece02683ce0faf21 ] Now that bpf_throw kfunc is the first such call instruction that has noreturn semantics within the verifier, this also kicks in dead code elimination in unprecedented ways. For one, any instruction following a bpf_throw call will never be marked as seen. Moreover, if a callchain ends up throwing, any instructions after the call instruction to the eventually throwing subprog in callers will also never be marked as seen. The tempting way to fix this would be to emit extra 'int3' instructions which bump the jited_len of a program, and ensure that during runtime when a program throws, we can discover its boundaries even if the call instruction to bpf_throw (or to subprogs that always throw) is emitted as the final instruction in the program. An example of such a program would be this: do_something(): ... r0 = 0 exit foo(): r1 = 0 call bpf_throw r0 = 0 exit bar(cond): if r1 != 0 goto pc+2 call do_something exit call foo r0 = 0 // Never seen by verifier exit // main(ctx): r1 = ... call bar r0 = 0 exit Here, if we do end up throwing, the stacktrace would be the following: bpf_throw foo bar main In bar, the final instruction emitted will be the call to foo, as such, the return address will be the subsequent instruction (which the JIT emits as int3 on x86). This will end up lying outside the jited_len of the program, thus, when unwinding, we will fail to discover the return address as belonging to any program and end up in a panic due to the unreliable stack unwinding of BPF programs that we never expect. To remedy this case, make bpf_prog_ksym_find treat IP == ksym.end as part of the BPF program, so that is_bpf_text_address returns true when such a case occurs, and we are able to unwind reliably when the final instruction ends up being a call instruction. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20230912233214.1518551-12-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-11-28 17:06:55 +00:00
..
bpf	bpf: Detect IP == ksym.end as part of BPF program	2023-11-28 17:06:55 +00:00
cgroup	cgroup: Remove duplicates in cgroup v1 tasks file	2023-10-19 23:08:57 +02:00
configs	Kbuild: add Rust support	2022-09-28 09:02:20 +02:00
debug	mm: remove vmacache	2022-09-26 19:46:18 -07:00
dma	dma-debug: don't call __dma_entry_alloc_check_leak() under free_entries_lock	2023-10-06 14:56:50 +02:00
entry	entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up	2023-03-30 12:49:13 +02:00
events	perf/core: Bail out early if the request AUX area is out of bound	2023-11-28 17:06:54 +00:00
futex	futex: Don't include process MM in futex key on no-MMU	2023-11-20 11:51:50 +01:00
gcov	gcov: add support for checksum field	2022-12-31 13:33:11 +01:00
irq	genirq/matrix: Exclude managed interrupts in irq_matrix_allocated()	2023-11-20 11:51:51 +01:00
kcsan	kcsan: Don't expect 64 bits atomic builtins from 32 bits architectures	2023-07-19 16:21:37 +02:00
livepatch	livepatch: Fix missing newline character in klp_resolve_symbols()	2023-11-20 11:52:10 +01:00
locking	locking/ww_mutex/test: Fix potential workqueue corruption	2023-11-28 17:06:54 +00:00
module	module/decompress: use vmalloc() for gzip decompression workspace	2023-11-20 11:52:03 +01:00
power	PM: QoS: Restore support for default value on frequency QoS	2023-07-23 13:49:45 +02:00
printk	printk: Consolidate console deferred printing	2023-09-23 11:11:07 +02:00
rcu	srcu: Fix srcu_struct node grpmask overflow on 64-bit systems	2023-11-28 17:06:54 +00:00
sched	sched: Fix stop_one_cpu_nowait() vs hotplug	2023-11-20 11:51:50 +01:00
time	tick/rcu: Fix false positive "softirq work is pending" messages	2023-09-13 09:42:57 +02:00
trace	tracing/kprobes: Fix the order of argument descriptions	2023-11-20 11:52:18 +01:00
.gitignore
acct.c	acct: fix potential integer overflow in encode_comp_t()	2022-12-31 13:32:58 +01:00
async.c
audit.c	audit: use time_after to compare time	2022-08-29 19:47:03 -04:00
audit.h	audit: remove selinux_audit_rule_update() declaration	2022-09-07 11:30:15 -04:00
audit_fsnotify.c	audit: fix potential double free on error path from fsnotify_add_inode_mark	2022-08-22 18:50:06 -04:00
audit_tree.c
audit_watch.c	audit_init_parent(): constify path	2022-09-01 17:39:30 -04:00
auditfilter.c
auditsc.c	audit,io_uring: io_uring openat triggers audit reference count underflow	2023-10-25 12:03:04 +02:00
backtracetest.c
bounds.c	mm: multi-gen LRU: minimal implementation	2022-09-26 19:46:09 -07:00
capability.c
cfi.c	cfi: Switch to -fsanitize=kcfi	2022-09-26 10:13:13 -07:00
compat.c	sched_getaffinity: don't assume 'cpumask_size()' is fully initialized	2023-04-06 12:10:40 +02:00
configs.c
context_tracking.c	context_tracking: Fix noinstr vs KASAN	2023-03-10 09:33:45 +01:00
cpu.c	cpu/hotplug: Don't offline the last non-isolated CPU	2023-11-28 17:06:55 +00:00
cpu_pm.c	context_tracking: Take IRQ eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
crash_core.c	vmcoreinfo: add kallsyms_num_syms symbol	2022-08-28 14:02:44 -07:00
crash_dump.c
cred.c
delayacct.c	delayacct: support re-entrance detection of thrashing accounting	2022-09-26 19:46:07 -07:00
dma.c
exec_domain.c
exit.c	exit: Detect and fix irq disabled state in oops	2023-03-10 09:33:45 +01:00
extable.c	context_tracking: Take NMI eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
fail_function.c	kernel/fail_function: fix memory leak with using debugfs_lookup()	2023-03-11 13:55:39 +01:00
fork.c	kernel/fork: beware of __put_task_struct() calling context	2023-09-23 11:11:00 +02:00
freezer.c	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
gen_kheaders.sh	kbuild: build init/built-in.a just once	2022-09-29 04:40:15 +09:00
groups.c	security: Add LSM hook to setgroups() syscall	2022-07-15 18:21:49 +00:00
hung_task.c	sched: Fix more TASK_state comparisons	2022-09-30 16:50:39 +02:00
iomem.c
irq_work.c
jump_label.c	jump_label: make initial NOP patching the special case	2022-06-24 09:48:55 +02:00
kallsyms.c	kallsyms: Add helper kallsyms_on_each_match_symbol()	2023-10-25 12:03:16 +02:00
kallsyms_internal.h	kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[]	2023-10-25 12:03:16 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: kmsan: unpoison area->list in kcov_remote_area_put()	2022-10-03 14:03:23 -07:00
kexec.c	panic, kexec: make __crash_kexec() NMI safe	2022-09-11 21:55:06 -07:00
kexec_core.c	kexec: fix a memory leak in crash_shrink_memory()	2023-07-19 16:21:08 +02:00
kexec_elf.c
kexec_file.c	kexec: support purgatories with .text.hot sections	2023-06-21 16:00:55 +02:00
kexec_internal.h	panic, kexec: make __crash_kexec() NMI safe	2022-09-11 21:55:06 -07:00
kheaders.c	kheaders: Use array declaration instead of char	2023-05-11 23:03:02 +09:00
kmod.c
kprobes.c	kprobes: Prohibit probing on CFI preamble symbol	2023-09-13 09:42:23 +02:00
ksysfs.c	kexec: turn all kexec_mutex acquisitions into trylocks	2022-09-11 21:55:06 -07:00
kthread.c	signal: break out of wait loops on kthread_stop()	2022-10-09 16:01:59 -07:00
latencytop.c	latencytop: use the last element of latency_record of system	2022-09-11 21:55:12 -07:00
Makefile	cfi: Fix CFI failure with KASAN	2022-12-31 13:33:08 +01:00
module_signature.c
notifier.c
nsproxy.c	Revert "fs/exec: allow to unshare a time namespace on vfork+exec"	2022-09-13 10:38:43 -07:00
padata.c	padata: Fix refcnt handling in padata_free_shell()	2023-11-20 11:52:07 +01:00
panic.c	panic: Reenable preemption in WARN slowpath	2023-09-23 11:11:09 +02:00
params.c
pid.c	gfs2: Add glockfd debugfs file	2022-06-29 13:07:16 +02:00
pid_namespace.c	rcu-tasks: Fix synchronize_rcu_tasks() VS zap_pid_ns_processes()	2023-03-10 09:32:52 +01:00
profile.c	kernel/profile.c: simplify duplicated code in profile_setup()	2022-09-11 21:55:12 -07:00
ptrace.c	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
range.c
reboot.c	kernel/reboot: Add SYS_OFF_MODE_RESTART_PREPARE mode	2022-10-04 15:59:36 +02:00
regset.c
relay.c	relayfs: fix out-of-bounds access in relay_file_read	2023-05-11 23:03:03 +09:00
resource.c	PCI: Allow drivers to request exclusive config regions	2023-09-13 09:42:46 +02:00
resource_kunit.c
rseq.c	rseq: Use pr_warn_once() when deprecated/unknown ABI flags are encountered	2022-11-14 09:58:32 +01:00
scftorture.c	scftorture: Forgive memory-allocation failure if KASAN	2023-09-23 11:11:00 +02:00
scs.c
seccomp.c
signal.c	mm: suppress mm fault logging if fatal signal already pending	2023-08-03 10:24:01 +02:00
smp.c	smp,csd: Throw an error if a CSD lock is stuck for too long	2023-11-28 17:06:55 +00:00
smpboot.c	smpboot: use atomic_try_cmpxchg in cpu_wait_death and cpu_report_death	2022-09-11 21:55:10 -07:00
smpboot.h
softirq.c	context_tracking: Take IRQ eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
stackleak.c
stacktrace.c
static_call.c
static_call_inline.c
stop_machine.c
sys.c	kernel/sys.c: fix and improve control flow in __sys_setres[ug]id()	2023-04-26 14:28:39 +02:00
sys_ni.c	kernel/sys_ni: add compat entry for fadvise64_64	2022-08-20 15:17:45 -07:00
sysctl-test.c	kernel/sysctl-test: use SYSCTL_{ZERO/ONE_HUNDRED} instead of i_{zero/one_hundred}	2022-09-08 16:56:45 -07:00
sysctl.c	proc: proc_skip_spaces() shouldn't think it is working on C strings	2022-12-05 12:09:06 -08:00
task_work.c	task_work: use try_cmpxchg in task_work_add, task_work_cancel_match and task_work_run	2022-09-11 21:55:10 -07:00
taskstats.c	genetlink: start to validate reserved header bytes	2022-08-29 12:47:15 +01:00
torture.c	torture: Fix hang during kthread shutdown phase	2023-03-10 09:34:07 +01:00
tracepoint.c	tracepoint: Optimize the critical region of mutex_lock in tracepoint_module_coming()	2022-09-26 13:01:18 -04:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c	freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL	2023-02-22 12:59:50 +01:00
up.c
user-return-notifier.c
user.c
user_namespace.c	ucounts: Split rlimit and ucount values and max values	2022-10-09 16:24:05 -07:00
usermode_driver.c
utsname.c
utsname_sysctl.c	kernel/utsname_sysctl.c: Fix hostname polling	2022-10-23 12:01:01 -07:00
watch_queue.c	watch_queue: prevent dangling pipe pointer	2023-07-19 16:22:10 +02:00
watchdog.c	powerpc updates for 6.0	2022-08-06 16:38:17 -07:00
watchdog_hld.c	watchdog/perf: more properly prevent false positives with turbo modes	2023-07-19 16:21:08 +02:00
workqueue.c	workqueue: Provide one lock class key per work_on_cpu() callsite	2023-11-28 17:06:55 +00:00
workqueue_internal.h