On Wed, Sep 20, 2023 at 6:30 PM Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx> wrote: > > KCSAN reported hundreds of instances of data-races in ACPICA like this one: > > [ 6.994149] ================================================================== > [ 6.994443] BUG: KCSAN: data-race in acpi_ut_status_exit / acpi_ut_trace > > [ 6.994795] write to 0xffffffffbae5a884 of 4 bytes by task 0 on cpu 2: > [ 6.994944] acpi_ut_status_exit (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/utdebug.c:467) > [ 6.994957] acpi_hw_register_read (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwregs.c:563) > [ 6.994968] acpi_read_bit_register (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwxface.c:171) > [ 6.994980] acpi_idle_bm_check (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:511) > [ 6.994990] acpi_idle_enter_bm (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:644 (discriminator 1)) > [ 6.995000] acpi_idle_enter (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:695) > [ 6.995010] cpuidle_enter_state (/home/marvin/linux/kernel/torvalds2/drivers/cpuidle/cpuidle.c:267) > [ 6.995019] cpuidle_enter (/home/marvin/linux/kernel/torvalds2/drivers/cpuidle/cpuidle.c:390) > [ 6.995027] call_cpuidle (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:135) > [ 6.995038] do_idle (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:219 /home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:282) > [ 6.995046] cpu_startup_entry (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:378 (discriminator 1)) > [ 6.995055] start_secondary (/home/marvin/linux/kernel/torvalds2/arch/x86/kernel/smpboot.c:210 /home/marvin/linux/kernel/torvalds2/arch/x86/kernel/smpboot.c:294) > [ 6.995066] secondary_startup_64_no_verify (/home/marvin/linux/kernel/torvalds2/arch/x86/kernel/head_64.S:433) > > [ 6.995121] read to 0xffffffffbae5a884 of 4 bytes by task 0 on cpu 9: > [ 6.995267] acpi_ut_trace (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/utdebug.c:263) > [ 6.995279] acpi_hw_validate_io_request (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwvalid.c:101) > [ 6.995291] acpi_hw_read_port (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwvalid.c:202) > [ 6.995303] acpi_hw_read (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwregs.c:251) > [ 6.995313] acpi_hw_register_read (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwregs.c:725 /home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwregs.c:499) > [ 6.995325] acpi_read_bit_register (/home/marvin/linux/kernel/torvalds2/drivers/acpi/acpica/hwxface.c:171) > [ 6.995336] acpi_idle_bm_check (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:511) > [ 6.995346] acpi_idle_enter_bm (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:644 (discriminator 1)) > [ 6.995356] acpi_idle_enter (/home/marvin/linux/kernel/torvalds2/drivers/acpi/processor_idle.c:695) > [ 6.995366] cpuidle_enter_state (/home/marvin/linux/kernel/torvalds2/drivers/cpuidle/cpuidle.c:267) > [ 6.995375] cpuidle_enter (/home/marvin/linux/kernel/torvalds2/drivers/cpuidle/cpuidle.c:390) > [ 6.995383] call_cpuidle (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:135) > [ 6.995394] do_idle (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:219 /home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:282) > [ 6.995402] cpu_startup_entry (/home/marvin/linux/kernel/torvalds2/kernel/sched/idle.c:378 (discriminator 1)) > [ 6.995411] start_secondary (/home/marvin/linux/kernel/torvalds2/arch/x86/kernel/smpboot.c:210 /home/marvin/linux/kernel/torvalds2/arch/x86/kernel/smpboot.c:294) > [ 6.995422] secondary_startup_64_no_verify (/home/marvin/linux/kernel/torvalds2/arch/x86/kernel/head_64.S:433) > > [ 6.995476] value changed: 0x00000004 -> 0x00000002 > > [ 6.995629] Reported by Kernel Concurrency Sanitizer on: > [ 6.995748] CPU: 9 PID: 0 Comm: swapper/9 Not tainted 6.6.0-rc2-kcsan-00003-g16819584c239-dirty #21 > [ 6.995758] Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023 > [ 6.995765] ================================================================== > > Please find the complete list at: https://domac.alu.unizg.hr/~mtodorov/linux/patches/acpica_utdebug/acpi_ut_status_exit.log.xz > > A number of unprotected increments: > > acpi_gbl_nesting_level++; > > and conditional statements: > > if (acpi_gbl_nesting_level) { > acpi_gbl_nesting_level--; > } > > no longer work in SMP environment. > > Proper locking like > > spin_lock(&acpi_utdebug_lock); > acpi_gbl_nesting_level++; > spin_unlock(&acpi_utdebug_lock); > > and > > spin_lock(&acpi_utdebug_lock); > if (acpi_gbl_nesting_level) { > acpi_gbl_nesting_level--; > } > spin_unlock(&acpi_utdebug_lock); > > makes these data-races go away. > > Additionally, READ_ONCE() or WRITE_ONCE() is required with the global variable > acpi_gbl_nesting_level to prevent unwanted read or write reordering or other funny > stuff the optmisers do. > > The patch eliminates KCSAN BUG warnings. > > Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx> > Fixes: 6be2d72b18649 ("ACPICA: Update for a few debug output statements") > Fixes: bf9b448ef8430 ("ACPICA: Debug output: Do not emit function nesting level for kernel build.") > Fixes: 6e875fa0480c1 ("ACPICA: Debugger: fix slight indentation issue") > Fixes: ^1da177e4c3f4 ("Initial git repository build.") > Cc: Jung-uk Kim <jkim@xxxxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Erik Kaneda <erik.kaneda@xxxxxxxxx> > Cc: Bob Moore <robert.moore@xxxxxxxxx> > Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> > Cc: Len Brown <lenb@xxxxxxxxxx> > Cc: linux-acpi@xxxxxxxxxxxxxxx > Cc: acpica-devel@xxxxxxxxxxxxxxxxxxxxxxxxx > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-kbuild-all/202309201331.S2c1JL2h-lkp@xxxxxxxxx/ > Closes: https://lore.kernel.org/oe-kbuild-all/202309201308.5ZBJFbjh-lkp@xxxxxxxxx/ > Link: https://github.com/acpica/acpica/pull/893 > Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx> > --- > v2 -> v3: > Made the pull request at the ACPICA github. > Fixed DEFINE_SPINLOCK() undefined warning by putting it inside #ifdef ACPI_DEBUG_OUTPUT > ... #endif > Capitalised ACPICA according to the convention. > > v1 -> v2: > Moved the declaration of 'u32 nesting_level' inside #ifdef ACPI_APPLICATION ... #endif > according to the unused variable warning of the kernel test robot. > > v1: > Preliminary RFC version of the patch. > > drivers/acpi/acpica/utdebug.c | 49 +++++++++++++++++++++++++---------- > 1 file changed, 35 insertions(+), 14 deletions(-) > > diff --git a/drivers/acpi/acpica/utdebug.c b/drivers/acpi/acpica/utdebug.c > index c5f6c85a3a09..594eee294f0f 100644 > --- a/drivers/acpi/acpica/utdebug.c > +++ b/drivers/acpi/acpica/utdebug.c > @@ -15,8 +15,9 @@ > > #define _COMPONENT ACPI_UTILITIES > ACPI_MODULE_NAME("utdebug") > - > #ifdef ACPI_DEBUG_OUTPUT > +static DEFINE_SPINLOCK(acpi_utdebug_lock); No, you can't do that in the ACPICA code. Likewise for other Linux-specific pieces of code in the patch below. I'd very much prefer you to send a proper problem report instead of sending patches like this. As it stands, I'm not even sure what problem exactly this is attempting to address. Thanks!
