| Message ID | 20230920162222.3614-1-mirsad.todorovac@alu.unizg.hr (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | [v3,1/1] ACPICA: utdebug: use spinlocks to fix the data-races reported by the KCSAN | expand |
On Wed, Sep 20, 2023 at 6:30 PM Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> 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@alu.unizg.hr> > 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@FreeBSD.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Erik Kaneda <erik.kaneda@intel.com> > Cc: Bob Moore <robert.moore@intel.com> > Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> > Cc: Len Brown <lenb@kernel.org> > Cc: linux-acpi@vger.kernel.org > Cc: acpica-devel@lists.linuxfoundation.org > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202309201331.S2c1JL2h-lkp@intel.com/ > Closes: https://lore.kernel.org/oe-kbuild-all/202309201308.5ZBJFbjh-lkp@intel.com/ > Link: https://github.com/acpica/acpica/pull/893 > Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> > --- > 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!
On 9/20/23 19:03, Rafael J. Wysocki wrote: > On Wed, Sep 20, 2023 at 6:30 PM Mirsad Goran Todorovac > <mirsad.todorovac@alu.unizg.hr> 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@alu.unizg.hr> >> 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@FreeBSD.org> >> Cc: Linus Torvalds <torvalds@linux-foundation.org> >> Cc: Erik Kaneda <erik.kaneda@intel.com> >> Cc: Bob Moore <robert.moore@intel.com> >> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> >> Cc: Len Brown <lenb@kernel.org> >> Cc: linux-acpi@vger.kernel.org >> Cc: acpica-devel@lists.linuxfoundation.org >> Reported-by: kernel test robot <lkp@intel.com> >> Closes: https://lore.kernel.org/oe-kbuild-all/202309201331.S2c1JL2h-lkp@intel.com/ >> Closes: https://lore.kernel.org/oe-kbuild-all/202309201308.5ZBJFbjh-lkp@intel.com/ >> Link: https://github.com/acpica/acpica/pull/893 >> Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> >> --- >> 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. I was so enthusiastic about the patch that cleared all the KCSAN data-race bug warnings, that I must have forgot about sending one. Patching of hundreds of annoying KCSAN acpi warnings seemed so good that I forgot about the procedure, sorry. I am aware that the maintainers have to carefully evaluate any contribution in order for the kernel not becoming bloated and unstable ... > As it stands, I'm not even sure what problem exactly this is > attempting to address. I hope the attached excerpt from the dmesg log will help. > Thanks! Anytime. Best regards, Mirsad Todorovac
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); + static acpi_thread_id acpi_gbl_previous_thread_id = (acpi_thread_id) 0xFFFFFFFF; static const char *acpi_gbl_function_entry_prefix = "----Entry"; static const char *acpi_gbl_function_exit_prefix = "----Exit-"; @@ -65,9 +66,11 @@ void acpi_ut_track_stack_ptr(void) acpi_gbl_lowest_stack_pointer = ¤t_sp; } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level > acpi_gbl_deepest_nesting) { acpi_gbl_deepest_nesting = acpi_gbl_nesting_level; } + spin_unlock(&acpi_utdebug_lock); } /******************************************************************************* @@ -136,6 +139,7 @@ acpi_debug_print(u32 requested_debug_level, va_list args; #ifdef ACPI_APPLICATION int fill_count; + u32 nesting_level; #endif /* Check if debug output enabled */ @@ -152,11 +156,12 @@ acpi_debug_print(u32 requested_debug_level, if (ACPI_LV_THREADS & acpi_dbg_level) { acpi_os_printf ("\n**** Context Switch from TID %u to TID %u ****\n\n", - (u32)acpi_gbl_previous_thread_id, (u32)thread_id); + (u32) acpi_gbl_previous_thread_id, + (u32) thread_id); } acpi_gbl_previous_thread_id = thread_id; - acpi_gbl_nesting_level = 0; + WRITE_ONCE(acpi_gbl_nesting_level, 0); } /* @@ -173,17 +178,18 @@ acpi_debug_print(u32 requested_debug_level, * level. */ if (ACPI_LV_THREADS & acpi_dbg_level) { - acpi_os_printf("[%u] ", (u32)thread_id); + acpi_os_printf("[%u] ", (u32) thread_id); } - fill_count = 48 - acpi_gbl_nesting_level - + nesting_level = READ_ONCE(acpi_gbl_nesting_level); + + fill_count = 48 - nesting_level - strlen(acpi_ut_trim_function_name(function_name)); if (fill_count < 0) { fill_count = 0; } - acpi_os_printf("[%02d] %*s", - acpi_gbl_nesting_level, acpi_gbl_nesting_level + 1, " "); + acpi_os_printf("[%02d] %*s", nesting_level, nesting_level + 1, " "); acpi_os_printf("%s%*s: ", acpi_ut_trim_function_name(function_name), fill_count, " "); @@ -198,7 +204,6 @@ acpi_debug_print(u32 requested_debug_level, } ACPI_EXPORT_SYMBOL(acpi_debug_print) - /******************************************************************************* * * FUNCTION: acpi_debug_print_raw @@ -238,7 +243,6 @@ acpi_debug_print_raw(u32 requested_debug_level, } ACPI_EXPORT_SYMBOL(acpi_debug_print_raw) - /******************************************************************************* * * FUNCTION: acpi_ut_trace @@ -260,7 +264,10 @@ acpi_ut_trace(u32 line_number, const char *module_name, u32 component_id) { + spin_lock(&acpi_utdebug_lock); acpi_gbl_nesting_level++; + spin_unlock(&acpi_utdebug_lock); + acpi_ut_track_stack_ptr(); /* Check if enabled up-front for performance */ @@ -274,7 +281,6 @@ acpi_ut_trace(u32 line_number, } ACPI_EXPORT_SYMBOL(acpi_ut_trace) - /******************************************************************************* * * FUNCTION: acpi_ut_trace_ptr @@ -298,7 +304,10 @@ acpi_ut_trace_ptr(u32 line_number, u32 component_id, const void *pointer) { + spin_lock(&acpi_utdebug_lock); acpi_gbl_nesting_level++; + spin_unlock(&acpi_utdebug_lock); + acpi_ut_track_stack_ptr(); /* Check if enabled up-front for performance */ @@ -334,7 +343,10 @@ acpi_ut_trace_str(u32 line_number, const char *module_name, u32 component_id, const char *string) { + spin_lock(&acpi_utdebug_lock); acpi_gbl_nesting_level++; + spin_unlock(&acpi_utdebug_lock); + acpi_ut_track_stack_ptr(); /* Check if enabled up-front for performance */ @@ -370,7 +382,10 @@ acpi_ut_trace_u32(u32 line_number, const char *module_name, u32 component_id, u32 integer) { + spin_lock(&acpi_utdebug_lock); acpi_gbl_nesting_level++; + spin_unlock(&acpi_utdebug_lock); + acpi_ut_track_stack_ptr(); /* Check if enabled up-front for performance */ @@ -414,13 +429,14 @@ acpi_ut_exit(u32 line_number, acpi_gbl_function_exit_prefix); } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level) { acpi_gbl_nesting_level--; } + spin_unlock(&acpi_utdebug_lock); } ACPI_EXPORT_SYMBOL(acpi_ut_exit) - /******************************************************************************* * * FUNCTION: acpi_ut_status_exit @@ -463,13 +479,14 @@ acpi_ut_status_exit(u32 line_number, } } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level) { acpi_gbl_nesting_level--; } + spin_unlock(&acpi_utdebug_lock); } ACPI_EXPORT_SYMBOL(acpi_ut_status_exit) - /******************************************************************************* * * FUNCTION: acpi_ut_value_exit @@ -502,13 +519,14 @@ acpi_ut_value_exit(u32 line_number, ACPI_FORMAT_UINT64(value)); } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level) { acpi_gbl_nesting_level--; } + spin_unlock(&acpi_utdebug_lock); } ACPI_EXPORT_SYMBOL(acpi_ut_value_exit) - /******************************************************************************* * * FUNCTION: acpi_ut_ptr_exit @@ -540,9 +558,11 @@ acpi_ut_ptr_exit(u32 line_number, acpi_gbl_function_exit_prefix, ptr); } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level) { acpi_gbl_nesting_level--; } + spin_unlock(&acpi_utdebug_lock); } /******************************************************************************* @@ -577,9 +597,11 @@ acpi_ut_str_exit(u32 line_number, acpi_gbl_function_exit_prefix, string); } + spin_lock(&acpi_utdebug_lock); if (acpi_gbl_nesting_level) { acpi_gbl_nesting_level--; } + spin_unlock(&acpi_utdebug_lock); } /******************************************************************************* @@ -612,5 +634,4 @@ acpi_trace_point(acpi_trace_event_type type, u8 begin, u8 *aml, char *pathname) } ACPI_EXPORT_SYMBOL(acpi_trace_point) - #endif
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@alu.unizg.hr> 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@FreeBSD.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Erik Kaneda <erik.kaneda@intel.com> Cc: Bob Moore <robert.moore@intel.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Len Brown <lenb@kernel.org> Cc: linux-acpi@vger.kernel.org Cc: acpica-devel@lists.linuxfoundation.org Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202309201331.S2c1JL2h-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202309201308.5ZBJFbjh-lkp@intel.com/ Link: https://github.com/acpica/acpica/pull/893 Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> --- 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(-)