Re: Bug in mmc_test or host driver?

[Adrian Hunter <adrian.hunter@nokia.com>]

Arnd Hannemann wrote:
> Hi,
> 
> if I peform the test 23 mmc_test_best_read_performance() with tmio_mmc
> on Linus tree, I hit the following BUG:
> 
>  [  152.625000] mmc0: Starting tests of card mmc0:2daf...
>  [  152.625000] mmc0: Test case 23. Best-case read performance...
>  [  152.632812] mmc0: starting CMD16 arg 00000200 flags 00000015
>  [  152.632812] MMC IRQ begin
>  [  152.632812] status: 208007a1 =
> SIGSTATEWRPROTECTCARD_REMOVE_ACARD_INSERT_ASIGSTATE_AILL_FUNCCMDRESPEND
>  [  152.632812] status: 00000001 = CMDRESPEND
>  [  152.632812] mmc0: req done (CMD16): 0: 00000900 00000900 00000b00
> 00000900
>  [  152.632812] Status at end of loop: 208007a0
>  [  152.632812] status: 208007a0 =
> SIGSTATEWRPROTECTCARD_REMOVE_ACARD_INSERT_ASIGSTATE_AILL_FUNC
>  [  152.632812] MMC IRQ end
>  [  152.632812] mmc0: starting CMD25 arg 003b0000 flags 00000035
>  [  152.632812] mmc0:     blksz 512 blocks 8192 flags 00000100 tsac 300
> ms nsac 0
>  [  152.632812] mmc0:     CMD12 arg 00000000 flags 0000001d
>  [  152.632812] kernel BUG at drivers/mmc/core/core.c:172!
> 
> 
> core.c:  172         BUG_ON(mrq->data->blocks > host->max_blk_count);
> 
> The host's max_blk_count is 512, but mmc_test does not check and issues
> a request with 8192 blocks.
> So I believe the test is wrong here?

Yes.  Try this:

diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index 5dd8576..4fb8b10 100644
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -1328,6 +1328,10 @@ static int mmc_test_area_init(struct mmc_test_card *test, int erase, int fill)
 		t->max_sz = TEST_AREA_MAX_SIZE;
 	else
 		t->max_sz = (unsigned long)test->card->pref_erase << 9;
+	if (t->max_sz >> 9 > test->card->host->max_blk_count)
+		t->max_sz = test->card->host->max_blk_count << 9;
+	if (min_sz > t->max_sz)
+		min_sz = t->max_sz;
 	/*
 	 * Try to allocate enough memory for the whole area.  Less is OK
 	 * because the same memory can be mapped into the scatterlist more than


and if it works send a patch.

> 
>  [  152.656250] Backtrace:
>  [  152.656250] [<c0028e38>] (__bug+0x0/0x30) from [<c0181f88>]
> (mmc_wait_for_req+0x14c/0x228)
>  [  152.656250] [<c0181e3c>] (mmc_wait_for_req+0x0/0x228) from
> [<bf01840c>] (mmc_test_simple_transfer+0xb0/0x140 [mmc_test])
>  [  152.656250]  r7:cf1e3d28 r6:cf1ec000 r5:cf1e3db4 r4:cf318000
>  [  152.656250] [<bf01835c>] (mmc_test_simple_transfer+0x0/0x140
> [mmc_test]) from [<bf01993c>] (mmc_test_area_io+0x2fc/0x350 [mmc_test])
>  [  152.656250] [<bf019640>] (mmc_test_area_io+0x0/0x350 [mmc_test])
> from [<bf0199c4>] (mmc_test_area_fill+0x34/0x3c [mmc_test])
>  [  152.656250] [<bf019990>] (mmc_test_area_fill+0x0/0x3c [mmc_test])
> from [<bf019d10>] (mmc_test_area_init+0x238/0x264 [mmc_test])
>  [  152.656250] [<bf019ad8>] (mmc_test_area_init+0x0/0x264 [mmc_test])
> from [<bf019d8c>] (mmc_test_area_prepare_fill+0x18/0x1c [mmc_test])
>  [  152.656250] [<bf019d74>] (mmc_test_area_prepare_fill+0x0/0x1c
> [mmc_test]) from [<bf018a1c>] (mmc_test_store+0xf8/0x290 [mmc_test])
>  [  152.656250] [<bf018924>] (mmc_test_store+0x0/0x290 [mmc_test]) from
> [<c015541c>] (dev_attr_store+0x24/0x28)
>  [  152.656250]  r8:cf0f3010 r7:cf24fd60 r6:00000003 r5:cf1e3f70 r4:cf41bd88
>  [  152.656250] r3:00000003
>  [  152.656250] [<c01553f8>] (dev_attr_store+0x0/0x28) from [<c00ccad0>]
> (sysfs_write_file+0x110/0x144)
>  [  152.656250] [<c00cc9c0>] (sysfs_write_file+0x0/0x144) from
> [<c008a5c4>] (vfs_write+0xbc/0x138)
>  [  152.656250] [<c008a508>] (vfs_write+0x0/0x138) from [<c008a708>]
> (sys_write+0x44/0x70)
>  [  152.656250]  r8:00000000 r7:00000004 r6:00000003 r5:000d9408 r4:cf0f4420
>  [  152.656250] [<c008a6c4>] (sys_write+0x0/0x70) from [<c0025e60>]
> (ret_fast_syscall+0x0/0x30)
>  [  152.656250]  r9:cf1e2000 r8:c0025fe4 r6:00000003 r5:403305c8 r4:00000003
>  [  152.656250] Code: e59f0010 e1a01003 eb077a1d e3a03000 (e5833000)
> 
> Best regards,
> Arnd
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