Marco Elver ea6588abcc kcsan: Turn report_filterlist_lock into a raw_spinlock ... [ Upstream commit 59458fa4dd ] Ran Xiaokai reports that with a KCSAN-enabled PREEMPT_RT kernel, we can see splats like: | BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 | in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1 | preempt_count: 10002, expected: 0 | RCU nest depth: 0, expected: 0 | no locks held by swapper/1/0. | irq event stamp: 156674 | hardirqs last enabled at (156673): [<ffffffff81130bd9>] do_idle+0x1f9/0x240 | hardirqs last disabled at (156674): [<ffffffff82254f84>] sysvec_apic_timer_interrupt+0x14/0xc0 | softirqs last enabled at (0): [<ffffffff81099f47>] copy_process+0xfc7/0x4b60 | softirqs last disabled at (0): [<0000000000000000>] 0x0 | Preemption disabled at: | [<ffffffff814a3e2a>] paint_ptr+0x2a/0x90 | CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0+ #3 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 | Call Trace: | <IRQ> | dump_stack_lvl+0x7e/0xc0 | dump_stack+0x1d/0x30 | __might_resched+0x1a2/0x270 | rt_spin_lock+0x68/0x170 | kcsan_skip_report_debugfs+0x43/0xe0 | print_report+0xb5/0x590 | kcsan_report_known_origin+0x1b1/0x1d0 | kcsan_setup_watchpoint+0x348/0x650 | __tsan_unaligned_write1+0x16d/0x1d0 | hrtimer_interrupt+0x3d6/0x430 | __sysvec_apic_timer_interrupt+0xe8/0x3a0 | sysvec_apic_timer_interrupt+0x97/0xc0 | </IRQ> On a detected data race, KCSAN's reporting logic checks if it should filter the report. That list is protected by the report_filterlist_lock *non-raw* spinlock which may sleep on RT kernels. Since KCSAN may report data races in any context, convert it to a raw_spinlock. This requires being careful about when to allocate memory for the filter list itself which can be done via KCSAN's debugfs interface. Concurrent modification of the filter list via debugfs should be rare: the chosen strategy is to optimistically pre-allocate memory before the critical section and discard if unused. Link: https://lore.kernel.org/all/20240925143154.2322926-1-ranxiaokai627@163.com/ Reported-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Tested-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-12-14 19:51:35 +01:00
..
bpf	bpf: fix OOB devmap writes when deleting elements	2024-12-14 19:51:33 +01:00
cgroup	cgroup/bpf: only cgroup v2 can be attached by bpf programs	2024-12-14 19:50:48 +01:00
configs
debug
dma
entry
events
futex
gcov
irq
kcsan	kcsan: Turn report_filterlist_lock into a raw_spinlock	2024-12-14 19:51:35 +01:00
livepatch
locking
power
printk	seqlock/latch: Provide raw_read_seqcount_latch_retry()	2024-12-14 19:50:46 +01:00
rcu	rcu-tasks: Idle tasks on offline CPUs are in quiescent states	2024-12-14 19:50:41 +01:00
sched
time	seqlock/latch: Provide raw_read_seqcount_latch_retry()	2024-12-14 19:50:46 +01:00
trace	tracing: Fix cmp_entries_dup() to respect sort() comparison rules	2024-12-14 19:51:31 +01:00
.gitignore
acct.c
async.c
audit_fsnotify.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c	posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone	2024-11-14 13:13:39 +01:00
freezer.c
gen_kheaders.sh
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec_core.c
kexec_elf.c
kexec_file.c
kexec_internal.h
kexec.c
kheaders.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
module_signature.c
module_signing.c
module-internal.h
module.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c
profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource_kunit.c
resource.c
rseq.c
scftorture.c
scs.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c
static_call_inline.c
static_call.c
stop_machine.c
sys_ni.c
sys.c
sysctl-test.c
sysctl.c
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c	ucounts: fix counter leak in inc_rlimit_get_ucounts()	2024-11-14 13:13:42 +01:00
uid16.c
uid16.h
umh.c
up.c
user_namespace.c
user-return-notifier.c
user.c
usermode_driver.c
utsname_sysctl.c
utsname.c
watch_queue.c
watchdog_hld.c
watchdog.c
workqueue_internal.h
workqueue.c