On Thu, Feb 8, 2018 at 2:41 PM, Jia-Ju Bai <baijiaju1990@xxxxxxxxx> wrote: > > > On 2018/2/8 18:20, Rafael J. Wysocki wrote: >> >> On Thursday, February 8, 2018 11:13:10 AM CET Chris Wilson wrote: >>> >>> Quoting Rafael J. Wysocki (2018-02-08 09:51:41) >>>> >>>> On Thursday, January 25, 2018 11:13:41 AM CET Jia-Ju Bai wrote: >>>>> >>>>> After checking all possible call chains to acpi_os_execute here, >>>>> my tool finds that acpi_os_execute is never called in atomic context. >>>>> And acpi_os_execute calls acpi_debugger_create_thread >>>>> which calls mutex_lock, >>>>> thus it proves again that acpi_os_execute can >>>>> call functions which may sleep. >>>>> Thus GFP_ATOMIC is not necessary, and it can be replaced with >>>>> GFP_KERNEL. >>>>> >>>>> This is found by a static analysis tool named DCNS written by myself. >>>>> >>>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx> >>>>> --- >>>>> drivers/acpi/osl.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c >>>>> index 3bb46cb..8ee605e 100644 >>>>> --- a/drivers/acpi/osl.c >>>>> +++ b/drivers/acpi/osl.c >>>>> @@ -1066,7 +1066,7 @@ acpi_status acpi_os_execute(acpi_execute_type >>>>> type, >>>>> * having a static work_struct. >>>>> */ >>>>> - dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC); >>>>> + dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_KERNEL); >>>>> if (!dpc) >>>>> return AE_NO_MEMORY; >>>>> >>>> >>>> Applied, thanks! >>> >>> Hmm, not this patch per se, but >>> >>> https://intel-gfx-ci.01.org/tree/next/next-20180207/fi-bxt-dsi/dmesg0.log >>> [ 111.378236] BUG: sleeping function called from invalid context at >>> mm/slab.h:420 >>> [ 111.378259] in_atomic(): 1, irqs_disabled(): 1, pid: 1701, name: >>> gem_exec_flush >>> [ 111.378275] INFO: lockdep is turned off. >>> [ 111.378277] irq event stamp: 0 >>> [ 111.378280] hardirqs last enabled at (0): [< (null)>] >>> (null) >>> [ 111.378286] hardirqs last disabled at (0): [<00000000a01fa473>] >>> copy_process.part.7+0x2f1/0x1db0 >>> [ 111.378290] softirqs last enabled at (0): [<00000000a01fa473>] >>> copy_process.part.7+0x2f1/0x1db0 >>> [ 111.378292] softirqs last disabled at (0): [< (null)>] >>> (null) >>> [ 111.378293] Preemption disabled at: >>> [ 111.378298] [<ffffffffa18f14f6>] __mutex_lock+0x56/0x9b0 >>> [ 111.378311] CPU: 1 PID: 1701 Comm: gem_exec_flush Tainted: G U W >>> 4.15.0-next-20180207-g5d1c98967100-next-20180207 #1 >>> [ 111.378313] Hardware name: Intel Corp. Broxton P/Apollolake RVP1A, >>> BIOS APLKRVPA.X64.0150.B11.1608081044 08/08/2016 >>> [ 111.378314] Call Trace: >>> [ 111.378318] <IRQ> >>> [ 111.378323] dump_stack+0x5f/0x86 >>> [ 111.378328] ___might_sleep+0x1d9/0x240 >>> [ 111.378334] ? acpi_os_execute+0x2d/0x130 >>> [ 111.378338] kmem_cache_alloc_trace+0x1ae/0x2b0 >>> [ 111.378344] ? acpi_ev_asynch_enable_gpe+0x2d/0x2d >>> [ 111.378347] acpi_os_execute+0x2d/0x130 >>> [ 111.378351] acpi_ev_gpe_dispatch+0xd7/0x120 >>> [ 111.378355] acpi_ev_gpe_detect+0x156/0x195 >>> [ 111.378362] acpi_ev_sci_xrupt_handler+0x16/0x28 >>> [ 111.378365] acpi_irq+0xd/0x30 >>> [ 111.378369] __handle_irq_event_percpu+0x3c/0x340 >>> [ 111.378374] handle_irq_event_percpu+0x1b/0x50 >>> [ 111.378378] handle_irq_event+0x2f/0x50 >>> [ 111.378381] handle_fasteoi_irq+0x93/0x150 >>> [ 111.378386] handle_irq+0x11/0x20 >>> [ 111.378390] do_IRQ+0x5e/0x120 >>> [ 111.378395] common_interrupt+0xbb/0xbb >>> [ 111.378397] </IRQ> >>> >>> does tell us that acpi_os_execute() is called in irq context. >> >> Well, right, thanks! >> >> I overlooked this instance, so dropping the patch. > > > Sorry for my false positive. No worries. > My tool missed that acpi_ev_sci_xrupt_handler() is an interrupt handler, sorry. That just means that the tool is not perfect, which is nothing unusual. :-) I only would suggest double checking its findings before sending out patches next time. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
