rcu: kasan: record and print call_rcu() call stack

Patch series "kasan: memorize and print call_rcu stack", v8. This patchset improves KASAN reports by making them to have call_rcu() call stack information. It is useful for programmers to solve use-after-free or double-free memory issue. The KASAN report was as follows(cleaned up slightly): BUG: KASAN: use-after-free in kasan_rcu_reclaim+0x58/0x60 Freed by task 0: kasan_save_stack+0x24/0x50 kasan_set_track+0x24/0x38 kasan_set_free_info+0x18/0x20 __kasan_slab_free+0x10c/0x170 kasan_slab_free+0x10/0x18 kfree+0x98/0x270 kasan_rcu_reclaim+0x1c/0x60 Last call_rcu(): kasan_save_stack+0x24/0x50 kasan_record_aux_stack+0xbc/0xd0 call_rcu+0x8c/0x580 kasan_rcu_uaf+0xf4/0xf8 Generic KASAN will record the last two call_rcu() call stacks and print up to 2 call_rcu() call stacks in KASAN report. it is only suitable for generic KASAN. This feature considers the size of struct kasan_alloc_meta and kasan_free_meta, we try to optimize the structure layout and size, lets it get better memory consumption. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ This patch (of 4): This feature will record the last two call_rcu() call stacks and prints up to 2 call_rcu() call stacks in KASAN report. When call_rcu() is called, we store the call_rcu() call stack into slub alloc meta-data, so that the KASAN report can print rcu stack. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ [walter-zh.wu@mediatek.com: build fix] Link: http://lkml.kernel.org/r/20200710162401.23816-1-walter-zh.wu@mediatek.com

WWWalter Wu committed 6 years ago