CVE-2024-46789

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/slub: add check for s-&gt;flags in the alloc_tagging_slab_free_hook<br /> <br /> When enable CONFIG_MEMCG &amp; CONFIG_KFENCE &amp; CONFIG_KMEMLEAK, the following<br /> warning always occurs,This is because the following call stack occurred:<br /> mem_pool_alloc<br /> kmem_cache_alloc_noprof<br /> slab_alloc_node<br /> kfence_alloc<br /> <br /> Once the kfence allocation is successful,slab-&gt;obj_exts will not be empty,<br /> because it has already been assigned a value in kfence_init_pool.<br /> <br /> Since in the prepare_slab_obj_exts_hook function,we perform a check for<br /> s-&gt;flags &amp; (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE),the alloc_tag_add function<br /> will not be called as a result.Therefore,ref-&gt;ct remains NULL.<br /> <br /> However,when we call mem_pool_free,since obj_ext is not empty, it<br /> eventually leads to the alloc_tag_sub scenario being invoked. This is<br /> where the warning occurs.<br /> <br /> So we should add corresponding checks in the alloc_tagging_slab_free_hook.<br /> For __GFP_NO_OBJ_EXT case,I didn&amp;#39;t see the specific case where it&amp;#39;s using<br /> kfence,so I won&amp;#39;t add the corresponding check in<br /> alloc_tagging_slab_free_hook for now.<br /> <br /> [ 3.734349] ------------[ cut here ]------------<br /> [ 3.734807] alloc_tag was not set<br /> [ 3.735129] WARNING: CPU: 4 PID: 40 at ./include/linux/alloc_tag.h:130 kmem_cache_free+0x444/0x574<br /> [ 3.735866] Modules linked in: autofs4<br /> [ 3.736211] CPU: 4 UID: 0 PID: 40 Comm: ksoftirqd/4 Tainted: G W 6.11.0-rc3-dirty #1<br /> [ 3.736969] Tainted: [W]=WARN<br /> [ 3.737258] Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022<br /> [ 3.737875] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)<br /> [ 3.738501] pc : kmem_cache_free+0x444/0x574<br /> [ 3.738951] lr : kmem_cache_free+0x444/0x574<br /> [ 3.739361] sp : ffff80008357bb60<br /> [ 3.739693] x29: ffff80008357bb70 x28: 0000000000000000 x27: 0000000000000000<br /> [ 3.740338] x26: ffff80008207f000 x25: ffff000b2eb2fd60 x24: ffff0000c0005700<br /> [ 3.740982] x23: ffff8000804229e4 x22: ffff800082080000 x21: ffff800081756000<br /> [ 3.741630] x20: fffffd7ff8253360 x19: 00000000000000a8 x18: ffffffffffffffff<br /> [ 3.742274] x17: ffff800ab327f000 x16: ffff800083398000 x15: ffff800081756df0<br /> [ 3.742919] x14: 0000000000000000 x13: 205d344320202020 x12: 5b5d373038343337<br /> [ 3.743560] x11: ffff80008357b650 x10: 000000000000005d x9 : 00000000ffffffd0<br /> [ 3.744231] x8 : 7f7f7f7f7f7f7f7f x7 : ffff80008237bad0 x6 : c0000000ffff7fff<br /> [ 3.744907] x5 : ffff80008237ba78 x4 : ffff8000820bbad0 x3 : 0000000000000001<br /> [ 3.745580] x2 : 68d66547c09f7800 x1 : 68d66547c09f7800 x0 : 0000000000000000<br /> [ 3.746255] Call trace:<br /> [ 3.746530] kmem_cache_free+0x444/0x574<br /> [ 3.746931] mem_pool_free+0x44/0xf4<br /> [ 3.747306] free_object_rcu+0xc8/0xdc<br /> [ 3.747693] rcu_do_batch+0x234/0x8a4<br /> [ 3.748075] rcu_core+0x230/0x3e4<br /> [ 3.748424] rcu_core_si+0x14/0x1c<br /> [ 3.748780] handle_softirqs+0x134/0x378<br /> [ 3.749189] run_ksoftirqd+0x70/0x9c<br /> [ 3.749560] smpboot_thread_fn+0x148/0x22c<br /> [ 3.749978] kthread+0x10c/0x118<br /> [ 3.750323] ret_from_fork+0x10/0x20<br /> [ 3.750696] ---[ end trace 0000000000000000 ]---