On 05.08.2017 00:12, Helge Deller wrote:
> On the parisc platform I noticed the UBSAN warning below.
> Maybe nr_divisor isn't correctly initialized ?
>
> [ 18.625415]
> ================================================================================
> [ 18.726489] UBSAN: Undefined behaviour in
> ./drivers/scsi/sym53c8xx_2/sym_hipd.c:762:24
> [ 18.864911] index -1903078336 is out of range for type 'u32 [7]'
> [ 18.936779] CPU: 0 PID: 1 Comm: swapper Not tainted 4.13.0-rc3-32bit+ #427
> [ 19.019138] Backtrace:
> [ 19.047353] [<10191eb4>] show_stack+0x3c/0x50
> [ 19.100577] [<10ce82fc>] dump_stack+0x28/0x38
> [ 19.153826] [<10771b3c>] ubsan_epilogue+0x1c/0x60
> [ 19.211229] [<107722ec>] __ubsan_handle_out_of_bounds+0x68/0x80
> [ 19.283194] [<10924074>] sym_hcb_attach+0xc2c/0x3204
> [ 19.343724] [<107aaa38>] sba_dma_supported+0x4c/0x208
> [ 19.405291] [<10911984>] sym2_probe+0xd64/0x122c
> [ 19.461661] [<10501c64>] kernfs_add_one+0x328/0x354
I did some more debugging.
The offending line is:
period = (11 * div_10M[np->clock_divn - 1]) / (4 * np->clock_khz);
with those values
np->clock_divn = 7
np->clock_khz = 160000
div_10M[6] = 80000000
period gets calculated as:
period = 1375
which is correct.
I have no clue why UBSAN reports an error here.
There is no overflow in index for div_10M array, neither is there
a u32 overflow.
Ideas?
Helge
