+Tobin C. Harding <tobin@xxxxxxxxxx> On Wed, May 15, 2019 at 5:24 PM Uladzislau Rezki <urezki@xxxxxxxxx> wrote: > > Hello, Andrew. > > > An earlier version of this patch was accused of crashing the kernel: > > > > https://lists.01.org/pipermail/lkp/2019-April/010004.html > > > > does the v4 series address this? > I tried before to narrow down that crash but i did not succeed, so > i have never seen that before on my test environment as well as > during running lkp-tests including trinity test case: > > test-url: http://codemonkey.org.uk/projects/trinity/ > > But after analysis of the Call-trace and slob_alloc(): > > <snip> > [ 0.395722] Call Trace: > [ 0.395722] slob_alloc+0x1c9/0x240 > [ 0.395722] kmem_cache_alloc+0x70/0x80 > [ 0.395722] acpi_ps_alloc_op+0xc0/0xca > [ 0.395722] acpi_ps_get_next_arg+0x3fa/0x6ed > <snip> > > <snip> > /* Attempt to alloc */ > prev = sp->lru.prev; > b = slob_page_alloc(sp, size, align); > if (!b) > continue; > > /* Improve fragment distribution and reduce our average > * search time by starting our next search here. (see > * Knuth vol 1, sec 2.5, pg 449) */ > if (prev != slob_list->prev && > slob_list->next != prev->next) > list_move_tail(slob_list, prev->next); <- Crash is here in __list_add_valid() > break; > } > <snip> > > i see that it tries to manipulate with "prev" node that may be removed > from the list by slob_page_alloc() earlier if whole page is used. I think > that crash has to be fixed by the below commit: > > https://www.spinics.net/lists/mm-commits/msg137923.html > > it was introduced into 5.1-rc3 kernel. > > Why ("mm/vmalloc.c: keep track of free blocks for vmap allocation") > was accused is probably because it uses "kmem cache allocations with struct alignment" > instead of kmalloc()/kzalloc(). Maybe because of bigger size requests > it became easier to trigger the BUG. But that is theory. > > -- > Vlad Rezki -- Uladzislau Rezki
