From nobody Tue Nov 26 06:26:17 2024 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 14A761426C for ; Sun, 20 Oct 2024 07:08:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729408132; cv=none; b=jZBy/ppouV5IHn6bP7XySHXQc+/Elq6nhKjzklRVu9C0yzyfm1QJbrVt0LDc7Zcugq9SwPpmcfotIX+ET+F34ejWlu/EOYtvg50kiA0WpDlutnx/RHzLYZ20diYXMlCMbvXn/77X4XqBmeUVRoVoK9LyQdiO0Cu6ahJw1ZdcYFw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729408132; c=relaxed/simple; bh=QMiL4cA0pX0cwFCg2aR5P5zopBl0Q/7Gl3PjWIlvw9c=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=TXEKalKE7xpPMxvhitQRlkCdhhj3rF+qjtAns/TfHRhO+rYDGFp7v8dWSOis0tz1bBJLmdyf0WCigfpa7JvzJ/xySIPx3DlYkFlJU81voKM8FKwyEZPukCWHj26h/RDgJOmJ2RHHhKwLQBkHMpmKu7ZLE8bDsvtoN993DAVJhhM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=IvRPNWaD; arc=none smtp.client-ip=95.215.58.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="IvRPNWaD" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729408128; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LqIdPb7NeBf33hzfhwQNcfLF0EmzG7i1fDU5vSLYBC4=; b=IvRPNWaDmJOH8b9my6/BQXYfg6P491lWbqyLXriDEALj5L9ZfvuMwEDXL1s1UPPwfQ1QtR LInLiDNVXgCB5Asi8zG2uepate5c7akcTaoSHGkLNx6U9HI32tXtlIdmNUDMLymxbY49GH RL2jBcxqBdAcZcVEh1s4eUDvHSXHwok= From: Hao Ge To: surenb@google.com, kent.overstreet@linux.dev, akpm@linux-foundation.org Cc: yuzhao@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, hao.ge@linux.dev, Hao Ge Subject: [PATCH v3] mm/codetag: fix null pointer check logic for ref and tag Date: Sun, 20 Oct 2024 15:08:19 +0800 Message-Id: <20241020070819.307944-1-hao.ge@linux.dev> In-Reply-To: <20241018152925.138341-1-hao.ge@linux.dev> References: <20241018152925.138341-1-hao.ge@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Hao Ge When we compile and load lib/slub_kunit.c,it will cause a panic. The root cause is that __kmalloc_cache_noprof was directly called instead of kmem_cache_alloc,which resulted in no alloc_tag being allocated.This caused current->alloc_tag to be null,leading to a null pointer dereference in alloc_tag_ref_set. Despite the fact that my colleague Pei Xiao will later fix the code in slub_kunit.c,we still need fix null pointer check logic for ref and tag to avoid panic caused by a null pointer dereference. Here is the log for the panic: [ 74.779373][ T2158] Unable to handle kernel NULL pointer dereference at = virtual address 0000000000000020 [ 74.780130][ T2158] Mem abort info: [ 74.780406][ T2158] ESR =3D 0x0000000096000004 [ 74.780756][ T2158] EC =3D 0x25: DABT (current EL), IL =3D 32 bits [ 74.781225][ T2158] SET =3D 0, FnV =3D 0 [ 74.781529][ T2158] EA =3D 0, S1PTW =3D 0 [ 74.781836][ T2158] FSC =3D 0x04: level 0 translation fault [ 74.782288][ T2158] Data abort info: [ 74.782577][ T2158] ISV =3D 0, ISS =3D 0x00000004, ISS2 =3D 0x00000000 [ 74.783068][ T2158] CM =3D 0, WnR =3D 0, TnD =3D 0, TagAccess =3D 0 [ 74.783533][ T2158] GCS =3D 0, Overlay =3D 0, DirtyBit =3D 0, Xs =3D 0 [ 74.784010][ T2158] user pgtable: 4k pages, 48-bit VAs, pgdp=3D000000010= 5f34000 [ 74.784586][ T2158] [0000000000000020] pgd=3D0000000000000000, p4d=3D000= 0000000000000 [ 74.785293][ T2158] Internal error: Oops: 0000000096000004 [#1] SMP [ 74.785805][ T2158] Modules linked in: slub_kunit kunit ip6t_rpfilter ip= 6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat= ebtable_broute ip6table_nat ip6table_mangle 4 [ 74.790661][ T2158] CPU: 0 UID: 0 PID: 2158 Comm: kunit_try_catch Kdump:= loaded Tainted: G W N 6.12.0-rc3+ #2 [ 74.791535][ T2158] Tainted: [W]=3DWARN, [N]=3DTEST [ 74.791889][ T2158] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 = 02/06/2015 [ 74.792479][ T2158] pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSB= S BTYPE=3D--) [ 74.793101][ T2158] pc : alloc_tagging_slab_alloc_hook+0x120/0x270 [ 74.793607][ T2158] lr : alloc_tagging_slab_alloc_hook+0x120/0x270 [ 74.794095][ T2158] sp : ffff800084d33cd0 [ 74.794418][ T2158] x29: ffff800084d33cd0 x28: 0000000000000000 x27: 000= 0000000000000 [ 74.795095][ T2158] x26: 0000000000000000 x25: 0000000000000012 x24: fff= f80007b30e314 [ 74.795822][ T2158] x23: ffff000390ff6f10 x22: 0000000000000000 x21: 000= 0000000000088 [ 74.796555][ T2158] x20: ffff000390285840 x19: fffffd7fc3ef7830 x18: fff= fffffffffffff [ 74.797283][ T2158] x17: ffff8000800e63b4 x16: ffff80007b33afc4 x15: fff= f800081654c00 [ 74.798011][ T2158] x14: 0000000000000000 x13: 205d383531325420 x12: 5b5= d383734363537 [ 74.798744][ T2158] x11: ffff800084d337e0 x10: 000000000000005d x9 : 000= 00000ffffffd0 [ 74.799476][ T2158] x8 : 7f7f7f7f7f7f7f7f x7 : ffff80008219d188 x6 : c00= 00000ffff7fff [ 74.800206][ T2158] x5 : ffff0003fdbc9208 x4 : ffff800081edd188 x3 : 000= 0000000000001 [ 74.800932][ T2158] x2 : 0beaa6dee1ac5a00 x1 : 0beaa6dee1ac5a00 x0 : fff= f80037c2cb000 [ 74.801656][ T2158] Call trace: [ 74.801954][ T2158] alloc_tagging_slab_alloc_hook+0x120/0x270 [ 74.802494][ T2158] __kmalloc_cache_noprof+0x148/0x33c [ 74.802976][ T2158] test_kmalloc_redzone_access+0x4c/0x104 [slub_kunit] [ 74.803607][ T2158] kunit_try_run_case+0x70/0x17c [kunit] [ 74.804124][ T2158] kunit_generic_run_threadfn_adapter+0x2c/0x4c [kunit] [ 74.804768][ T2158] kthread+0x10c/0x118 [ 74.805141][ T2158] ret_from_fork+0x10/0x20 [ 74.805540][ T2158] Code: b9400a80 11000400 b9000a80 97ffd858 (f94012d3) [ 74.806176][ T2158] SMP: stopping secondary CPUs [ 74.808130][ T2158] Starting crashdump kernel... Fixes: e0a955bf7f61 ("mm/codetag: add pgalloc_tag_copy()") Suggested-by: Suren Baghdasaryan Acked-by: Yu Zhao Signed-off-by: Hao Ge Acked-by: Suren Baghdasaryan --- v3: Modify the code logic based on Suren's suggestions. Update title and commit message due to code logic change. Add Suggested-by: Suren Baghdasaryan Add Acked-by: Yu Zhao v2: Modify the errors in the title and commit message. Remove the empty lines that were mistakenly added in version v1. --- include/linux/alloc_tag.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 1f0a9ff23a2c..941deffc590d 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -135,18 +135,21 @@ static inline void alloc_tag_sub_check(union codetag_= ref *ref) {} #endif =20 /* Caller should verify both ref and tag to be valid */ -static inline void __alloc_tag_ref_set(union codetag_ref *ref, struct allo= c_tag *tag) +static inline bool __alloc_tag_ref_set(union codetag_ref *ref, struct allo= c_tag *tag) { alloc_tag_add_check(ref, tag); if (!ref || !tag) - return; + return false; =20 ref->ct =3D &tag->ct; + return true; } =20 -static inline void alloc_tag_ref_set(union codetag_ref *ref, struct alloc_= tag *tag) +static inline bool alloc_tag_ref_set(union codetag_ref *ref, struct alloc_= tag *tag) { - __alloc_tag_ref_set(ref, tag); + if (unlikely(!__alloc_tag_ref_set(ref, tag))) + return false; + /* * We need in increment the call counter every time we have a new * allocation or when we split a large allocation into smaller ones. @@ -154,12 +157,13 @@ static inline void alloc_tag_ref_set(union codetag_re= f *ref, struct alloc_tag *t * counter because when we free each part the counter will be decremented. */ this_cpu_inc(tag->counters->calls); + return true; } =20 static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag = *tag, size_t bytes) { - alloc_tag_ref_set(ref, tag); - this_cpu_add(tag->counters->bytes, bytes); + if (likely(alloc_tag_ref_set(ref, tag))) + this_cpu_add(tag->counters->bytes, bytes); } =20 static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) --=20 2.25.1