| Message ID | 20230414050836.1984746-2-mcgrof@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | module: avoid userspace pressure on unwanted allocations | expand |
On Thu, Apr 13, 2023 at 10:08:33PM -0700, Luis Chamberlain wrote: > Commit ac3b43283923 ("module: replace module_layout with module_memory") > reworked the way to handle memory allocations to make it clearer. But it > lost in translation how we handled kmemleak_ignore() or kmemleak_not_leak() > for different ELF sections. > > Fix this and clarify the comments a bit more. Contrary to the old way > of using kmemleak_ignore() for init.* ELF sections we stick now only to > kmemleak_not_leak() as per suggestion by Catalin Marinas so to avoid > any false positives and simplify the code. > > Fixes: ac3b43283923 ("module: replace module_layout with module_memory") > Reported-by: Jim Cromie <jim.cromie@gmail.com> > Acked-by: Song Liu <song@kernel.org> > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/kernel/module/main.c b/kernel/module/main.c index 5cc21083af04..32554d8a5791 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2231,13 +2231,18 @@ static int move_module(struct module *mod, struct load_info *info) } mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size); ptr = module_memory_alloc(mod->mem[type].size, type); - /* - * The pointer to this block is stored in the module structure - * which is inside the block. Just mark it as not being a - * leak. + * The pointer to these blocks of memory are stored on the module + * structure and we keep that around so long as the module is + * around. We only free that memory when we unload the module. + * Just mark them as not being a leak then. The .init* ELF + * sections *do* get freed after boot so we *could* treat them + * slightly differently with kmemleak_ignore() and only grey + * them out as they work as typical memory allocations which + * *do* eventually get freed, but let's just keep things simple + * and avoid *any* false positives. */ - kmemleak_ignore(ptr); + kmemleak_not_leak(ptr); if (!ptr) { t = type; goto out_enomem;
Commit ac3b43283923 ("module: replace module_layout with module_memory") reworked the way to handle memory allocations to make it clearer. But it lost in translation how we handled kmemleak_ignore() or kmemleak_not_leak() for different ELF sections. Fix this and clarify the comments a bit more. Contrary to the old way of using kmemleak_ignore() for init.* ELF sections we stick now only to kmemleak_not_leak() as per suggestion by Catalin Marinas so to avoid any false positives and simplify the code. Fixes: ac3b43283923 ("module: replace module_layout with module_memory") Reported-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Song Liu <song@kernel.org> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> --- kernel/module/main.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)