Date: Sat, 28 Sep 2024 10:38:10 GMT From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 87d3af98590b - stable/14 - kern_malloc: fold free and zfree together into one __always_inline func Message-ID: <202409281038.48SAcA1Z097606@gitrepo.freebsd.org>
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The branch stable/14 has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=87d3af98590bbf09509822ec94c596d69f53411e commit 87d3af98590bbf09509822ec94c596d69f53411e Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2024-07-24 15:56:32 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2024-09-28 10:35:12 +0000 kern_malloc: fold free and zfree together into one __always_inline func free() and zfree() are essentially the same copy and pasted code with the extra explicit_bzero() (and formerly kasan) calls. Add a bool to add the extra functionality and make both functions a wrapper around the common code and let the compiler do the optimization based on the bool input when inlining. No functional changes intended. Suggested by: kib (in D45812) Sponsored by: The FreeBSD Foundation Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D46101 And the fix from Olivier Certner (olce): kern_malloc: Restore working KASAN runtime after free() and zfree() folding In the zfree() case, the explicit_bzero() calls zero all the allocation, including the redzone which malloc() has marked as invalid. So calling kasan_mark() before those is in fact necessary. This fixes a crash at boot when 'ldconfig' is run and tries to get random bytes through getrandom() (relevant part of the stack is read_random_uio() -> zfree() -> explicit_bzero()) for kernels with KASAN compiled in. Approved by: markj (mentor) Fixes: 4fab5f005482 ("kern_malloc: fold free and zfree together into one __always_inline func") Sponsored by: The FreeBSD Foundation (cherry picked from commit 4fab5f005482aa88bc0f7d7a0a5e81b436869112) (cherry picked from commit 28391f188ca18b6251ba46040adf81946b0ccb03) --- sys/kern/kern_malloc.c | 94 +++++++++++++++++--------------------------------- 1 file changed, 31 insertions(+), 63 deletions(-) diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c index 403f5fe11455..3fef90b5fa82 100644 --- a/sys/kern/kern_malloc.c +++ b/sys/kern/kern_malloc.c @@ -922,15 +922,8 @@ free_dbg(void **addrp, struct malloc_type *mtp) } #endif -/* - * free: - * - * Free a block of memory allocated by malloc. - * - * This routine may not block. - */ -void -free(void *addr, struct malloc_type *mtp) +static __always_inline void +_free(void *addr, struct malloc_type *mtp, bool dozero) { uma_zone_t zone; uma_slab_t slab; @@ -946,8 +939,8 @@ free(void *addr, struct malloc_type *mtp) vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab); if (slab == NULL) - panic("free: address %p(%p) has not been allocated", - addr, (void *)((u_long)addr & (~UMA_SLAB_MASK))); + panic("%s(%d): address %p(%p) has not been allocated", __func__, + dozero, addr, (void *)((uintptr_t)addr & (~UMA_SLAB_MASK))); switch (GET_SLAB_COOKIE(slab)) { case __predict_true(SLAB_COOKIE_SLAB_PTR): @@ -955,79 +948,54 @@ free(void *addr, struct malloc_type *mtp) #if defined(INVARIANTS) && !defined(KASAN) free_save_type(addr, mtp, size); #endif + if (dozero) { + kasan_mark(addr, size, size, 0); + explicit_bzero(addr, size); + } uma_zfree_arg(zone, addr, slab); break; case SLAB_COOKIE_MALLOC_LARGE: size = malloc_large_size(slab); + if (dozero) { + kasan_mark(addr, size, size, 0); + explicit_bzero(addr, size); + } free_large(addr, size); break; case SLAB_COOKIE_CONTIG_MALLOC: - size = contigmalloc_size(slab); + size = round_page(contigmalloc_size(slab)); + if (dozero) + explicit_bzero(addr, size); kmem_free(addr, size); - size = round_page(size); break; default: - panic("%s: addr %p slab %p with unknown cookie %d", __func__, - addr, slab, GET_SLAB_COOKIE(slab)); + panic("%s(%d): addr %p slab %p with unknown cookie %d", + __func__, dozero, addr, slab, GET_SLAB_COOKIE(slab)); /* NOTREACHED */ } malloc_type_freed(mtp, size); } /* - * zfree: - * - * Zero then free a block of memory allocated by malloc. - * + * free: + * Free a block of memory allocated by malloc/contigmalloc. * This routine may not block. */ void -zfree(void *addr, struct malloc_type *mtp) +free(void *addr, struct malloc_type *mtp) { - uma_zone_t zone; - uma_slab_t slab; - u_long size; - -#ifdef MALLOC_DEBUG - if (free_dbg(&addr, mtp) != 0) - return; -#endif - /* free(NULL, ...) does nothing */ - if (addr == NULL) - return; - - vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab); - if (slab == NULL) - panic("free: address %p(%p) has not been allocated", - addr, (void *)((u_long)addr & (~UMA_SLAB_MASK))); + _free(addr, mtp, false); +} - switch (GET_SLAB_COOKIE(slab)) { - case __predict_true(SLAB_COOKIE_SLAB_PTR): - size = zone->uz_size; -#if defined(INVARIANTS) && !defined(KASAN) - free_save_type(addr, mtp, size); -#endif - kasan_mark(addr, size, size, 0); - explicit_bzero(addr, size); - uma_zfree_arg(zone, addr, slab); - break; - case SLAB_COOKIE_MALLOC_LARGE: - size = malloc_large_size(slab); - kasan_mark(addr, size, size, 0); - explicit_bzero(addr, size); - free_large(addr, size); - break; - case SLAB_COOKIE_CONTIG_MALLOC: - size = round_page(contigmalloc_size(slab)); - explicit_bzero(addr, size); - kmem_free(addr, size); - break; - default: - panic("%s: addr %p slab %p with unknown cookie %d", __func__, - addr, slab, GET_SLAB_COOKIE(slab)); - /* NOTREACHED */ - } - malloc_type_freed(mtp, size); +/* + * zfree: + * Zero then free a block of memory allocated by malloc/contigmalloc. + * This routine may not block. + */ +void +zfree(void *addr, struct malloc_type *mtp) +{ + _free(addr, mtp, true); } /*
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