Messages in this thread | | | Date | Tue, 19 Feb 2019 19:46:11 +0200 | From | Mike Rapoport <> | Subject | Re: [PATCH] mm/cma: cma_declare_contiguous: correct err handling |
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On Tue, Feb 19, 2019 at 05:55:33PM +0100, Vlastimil Babka wrote: > On 2/14/19 9:38 PM, Andrew Morton wrote: > > On Thu, 14 Feb 2019 12:45:51 +0000 Peng Fan <peng.fan@nxp.com> wrote: > > > >> In case cma_init_reserved_mem failed, need to free the memblock allocated > >> by memblock_reserve or memblock_alloc_range. > >> > >> ... > >> > >> --- a/mm/cma.c > >> +++ b/mm/cma.c > >> @@ -353,12 +353,14 @@ int __init cma_declare_contiguous(phys_addr_t base, > >> > >> ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma); > >> if (ret) > >> - goto err; > >> + goto free_mem; > >> > >> pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, > >> &base); > >> return 0; > >> > >> +free_mem: > >> + memblock_free(base, size); > >> err: > >> pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); > >> return ret; > > > > This doesn't look right to me. In the `fixed==true' case we didn't > > actually allocate anything and in the `fixed==false' case, the > > allocated memory is at `addr', not at `base'. > > I think it's ok as the fixed==true path has "memblock_reserve()", but > better leave this to the memblock maintainer :)
As Peng Fan noted in the other e-mail, fixed==true has memblock_reserve() and fixed==false resets base = addr, so this is Ok.
> There's also 'kmemleak_ignore_phys(addr)' which should probably be > undone (or not called at all) in the failure case. But it seems to be > missing from the fixed==true path?
Well, memblock and kmemleak interaction does not seem to have clear semantics anyway. memblock_free() calls kmemleak_free_part_phys() which does not seem to care about ignored objects. As for the fixed==true path, memblock_reserve() does not register the area with kmemleak, so there would be no object to free in memblock_free(). AFAIU, kmemleak simply ignores this.
Catalin, can you comment please?
-- Sincerely yours, Mike.
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