Hi Gustavo A. R. Silva, Thanks for your patch!
> -----Original Message----- > From: Gustavo A. R. Silva <[email protected]> > Sent: Thursday, October 12, 2023 11:19 AM > To: Michael Turquette <[email protected]>; Stephen Boyd > <[email protected]>; iwamatsu nobuhiro(岩松 信洋 ○ＤＩＴＣ□ＤＩＴ○Ｏ > ＳＴ) <[email protected]> > Cc: Kees Cook <[email protected]>; [email protected]; > [email protected]; [email protected]; Gustavo A. > R. Silva <[email protected]>; [email protected] > Subject: [PATCH 2/2][next] clk: visconti: Add bounds-checking coverage for > struct visconti_pll_provider > > In order to gain the bounds-checking coverage that __counted_by provides to > flexible-array members at run-time via CONFIG_UBSAN_BOUNDS (for array > indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions), we must make sure that the counter member, in this particular case > `num`, is updated before the first access to the flex-array member, in this > particular case array `hws`. See below: > > commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with > __counted_by") introduced `__counted_by` for `struct clk_hw_onecell_data` > together with changes to relocate some of assignments of counter `num` > before `hws` is accessed: > > include/linux/clk-provider.h: > 1380 struct clk_hw_onecell_data { > 1381 unsigned int num; > 1382 struct clk_hw *hws[] __counted_by(num); > 1383 }; > > However, this structure is used as a member in other structs, in this case in > `struct visconti_pll_provider`: > > drivers/clk/visconti/pll.h: > 16 struct visconti_pll_provider { > 17 void __iomem *reg_base; > 18 struct device_node *node; > 19 > 20 /* Must be last */ > 21 struct clk_hw_onecell_data clk_data; > 22 }; > > Hence, we need to move the assignments to `ctx->clk_data.num` after > allocation for `struct visconti_pll_provider` and before accessing the > flexible > array `ctx->clk_data.hws`. And, as assignments for all members in `struct > visconti_pll_provider` are originally adjacent to each other, relocate all > assignments together, so we don't split up `ctx->clk_data.hws = nr_plls` from > the rest. :) > > Signed-off-by: Gustavo A. R. Silva <[email protected]> Acked-by: Nobuhiro Iwamatsu <[email protected]> Best regards, Nobuhiro
