On Tue, Dec 17, 2024 at 2:52 AM Sam Sun <samsun1006219@xxxxxxxxx> wrote: > > Dear developers and maintainers, > > We encountered a slab-use-after-free bug while using our modified > syzkaller. Kernel crash log is listed below. Thanks for reporting this! This seems to be the problem that Johannes pointed out in: https://lore.kernel.org/lkml/20241113213007.GB1564047@xxxxxxxxxxx/. Would you be able to check if the following diff fixes the problem? diff --git a/mm/zswap.c b/mm/zswap.c index 0030ce8fecfc5..089d70dee3246 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -875,6 +875,21 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) return 0; } +static void acomp_ctx_get_cpu(struct crypto_acomp_ctx *acomp_ctx) +{ + /* + * Prevent CPU hotplug from freeing this CPU's acomp_ctx until + * acomp_ctx_put_cpu(). + */ + cpus_read_lock(); + return raw_cpu_ptr +} + +static void acomp_ctx_put_cpu(void) +{ + cpus_read_unlock(); +} + static bool zswap_compress(struct folio *folio, struct zswap_entry *entry) { struct crypto_acomp_ctx *acomp_ctx; @@ -887,8 +902,7 @@ static bool zswap_compress(struct folio *folio, struct zswap_entry *entry) gfp_t gfp; u8 *dst; - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); - + acomp_ctx = acomp_ctx_get_cpu(entry->pool->acomp_ctx); mutex_lock(&acomp_ctx->mutex); dst = acomp_ctx->buffer; @@ -944,6 +958,7 @@ static bool zswap_compress(struct folio *folio, struct zswap_entry *entry) zswap_reject_alloc_fail++; mutex_unlock(&acomp_ctx->mutex); + acomp_ctx_put_cpu(); return comp_ret == 0 && alloc_ret == 0; } @@ -954,7 +969,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) struct crypto_acomp_ctx *acomp_ctx; u8 *src; - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); + acomp_ctx = acompx_ctx_get_cpu(entry->pool->acomp_ctx); mutex_lock(&acomp_ctx->mutex); src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO); @@ -984,6 +999,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) if (src != acomp_ctx->buffer) zpool_unmap_handle(zpool, entry->handle); + acomp_ctx_put_cpu(); } /********************************* > > > ================================================================== > BUG: KASAN: slab-use-after-free in zswap_decompress+0x7d7/0x810 mm/zswap.c:988 > Read of size 4 at addr ffff888027874044 by task kswapd0/92 > > CPU: 1 UID: 0 PID: 92 Comm: kswapd0 Not tainted 6.12.0-09435-g2c22dc1ee3a1 #11 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:94 [inline] > dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:378 [inline] > print_report+0xc0/0x5e0 mm/kasan/report.c:489 > kasan_report+0xbd/0xf0 mm/kasan/report.c:602 > zswap_decompress+0x7d7/0x810 mm/zswap.c:988 > zswap_writeback_entry+0x1e9/0x860 mm/zswap.c:1058 > shrink_memcg_cb+0x213/0x360 mm/zswap.c:1163 > __list_lru_walk_one+0x15e/0x490 mm/list_lru.c:301 > list_lru_walk_one+0x3e/0x50 mm/list_lru.c:338 > list_lru_shrink_walk include/linux/list_lru.h:240 [inline] > zswap_shrinker_scan+0x135/0x220 mm/zswap.c:1197 > do_shrink_slab+0x44e/0x1190 mm/shrinker.c:437 > shrink_slab_memcg mm/shrinker.c:550 [inline] > shrink_slab+0xb61/0x12a0 mm/shrinker.c:628 > shrink_one+0x4ad/0x7c0 mm/vmscan.c:4836 > shrink_many mm/vmscan.c:4897 [inline] > lru_gen_shrink_node mm/vmscan.c:4975 [inline] > shrink_node+0x269a/0x3d60 mm/vmscan.c:5956 > kswapd_shrink_node mm/vmscan.c:6785 [inline] > balance_pgdat+0xbe5/0x18c0 mm/vmscan.c:6977 > kswapd+0x6ff/0xd60 mm/vmscan.c:7246 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > </TASK> > > Allocated by task 1: > kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 > kasan_save_track+0x14/0x30 mm/kasan/common.c:68 > poison_kmalloc_redzone mm/kasan/common.c:377 [inline] > __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 > kasan_kmalloc include/linux/kasan.h:260 [inline] > __do_kmalloc_node mm/slub.c:4283 [inline] > __kmalloc_noprof+0x212/0x530 mm/slub.c:4295 > kmalloc_noprof include/linux/slab.h:905 [inline] > kzalloc_noprof include/linux/slab.h:1037 [inline] > __acomp_request_alloc_noprof include/crypto/internal/acompress.h:75 [inline] > acomp_request_alloc+0x46/0x110 crypto/acompress.c:131 > zswap_cpu_comp_prepare+0x1f4/0x470 mm/zswap.c:840 > cpuhp_invoke_callback+0x26d/0x9d0 kernel/cpu.c:204 > cpuhp_issue_call+0x1c1/0x8d0 kernel/cpu.c:2375 > __cpuhp_state_add_instance_cpuslocked+0x26a/0x3c0 kernel/cpu.c:2437 > __cpuhp_state_add_instance+0xd7/0x2e0 kernel/cpu.c:2458 > cpuhp_state_add_instance include/linux/cpuhotplug.h:386 [inline] > zswap_pool_create+0x2c3/0x5c0 mm/zswap.c:288 > __zswap_pool_create_fallback mm/zswap.c:356 [inline] > zswap_setup+0x3a5/0x820 mm/zswap.c:1781 > zswap_init+0x2d/0x40 mm/zswap.c:1817 > do_one_initcall+0x111/0x6d0 init/main.c:1266 > do_initcall_level init/main.c:1328 [inline] > do_initcalls init/main.c:1344 [inline] > do_basic_setup init/main.c:1363 [inline] > kernel_init_freeable+0x5ae/0x8a0 init/main.c:1577 > kernel_init+0x1e/0x2d0 init/main.c:1466 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Freed by task 25: > kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 > kasan_save_track+0x14/0x30 mm/kasan/common.c:68 > kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582 > poison_slab_object mm/kasan/common.c:247 [inline] > __kasan_slab_free+0x54/0x70 mm/kasan/common.c:264 > kasan_slab_free include/linux/kasan.h:233 [inline] > slab_free_hook mm/slub.c:2338 [inline] > slab_free mm/slub.c:4598 [inline] > kfree+0x14e/0x4d0 mm/slub.c:4746 > zswap_cpu_comp_dead+0xe3/0x1c0 mm/zswap.c:874 > cpuhp_invoke_callback+0x564/0x9d0 kernel/cpu.c:216 > __cpuhp_invoke_callback_range+0x104/0x220 kernel/cpu.c:965 > cpuhp_invoke_callback_range kernel/cpu.c:989 [inline] > cpuhp_down_callbacks kernel/cpu.c:1382 [inline] > _cpu_down+0x41d/0xef0 kernel/cpu.c:1443 > __cpu_down_maps_locked+0x6f/0x90 kernel/cpu.c:1473 > work_for_cpu_fn+0x55/0xa0 kernel/workqueue.c:6719 > process_one_work+0x9a2/0x1ba0 kernel/workqueue.c:3229 > process_scheduled_works kernel/workqueue.c:3310 [inline] > worker_thread+0x677/0xe90 kernel/workqueue.c:3391 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > The buggy address belongs to the object at ffff888027874000 > which belongs to the cache kmalloc-96 of size 96 > The buggy address is located 68 bytes inside of > freed 96-byte region [ffff888027874000, ffff888027874060) > > The buggy address belongs to the physical page: > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27874 > flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) > page_type: f5(slab) > raw: 00fff00000000000 ffff88801b041280 dead000000000100 dead000000000122 > raw: 0000000000000000 0000000000200020 00000001f5000000 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask > 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid > 1 (swapper/0), ts 20389586985, free_ts 18720773637 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x2e7/0x350 mm/page_alloc.c:1556 > prep_new_page mm/page_alloc.c:1564 [inline] > get_page_from_freelist+0xe4e/0x2b20 mm/page_alloc.c:3474 > __alloc_pages_noprof+0x219/0x21f0 mm/page_alloc.c:4751 > alloc_pages_mpol_noprof+0x2b6/0x600 mm/mempolicy.c:2265 > alloc_slab_page mm/slub.c:2408 [inline] > allocate_slab mm/slub.c:2574 [inline] > new_slab+0x2d5/0x420 mm/slub.c:2627 > ___slab_alloc+0xbb7/0x1850 mm/slub.c:3815 > __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3905 > __slab_alloc_node mm/slub.c:3980 [inline] > slab_alloc_node mm/slub.c:4141 [inline] > __do_kmalloc_node mm/slub.c:4282 [inline] > __kmalloc_noprof+0x2ac/0x530 mm/slub.c:4295 > kmalloc_noprof include/linux/slab.h:905 [inline] > kzalloc_noprof include/linux/slab.h:1037 [inline] > __acomp_request_alloc_noprof include/crypto/internal/acompress.h:75 [inline] > acomp_request_alloc+0x46/0x110 crypto/acompress.c:131 > zswap_cpu_comp_prepare+0x1f4/0x470 mm/zswap.c:840 > cpuhp_invoke_callback+0x26d/0x9d0 kernel/cpu.c:204 > cpuhp_issue_call+0x1c1/0x8d0 kernel/cpu.c:2375 > __cpuhp_state_add_instance_cpuslocked+0x26a/0x3c0 kernel/cpu.c:2437 > __cpuhp_state_add_instance+0xd7/0x2e0 kernel/cpu.c:2458 > cpuhp_state_add_instance include/linux/cpuhotplug.h:386 [inline] > zswap_pool_create+0x2c3/0x5c0 mm/zswap.c:288 > __zswap_pool_create_fallback mm/zswap.c:356 [inline] > zswap_setup+0x3a5/0x820 mm/zswap.c:1781 > page last free pid 54 tgid 54 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1127 [inline] > free_unref_page+0x714/0x10c0 mm/page_alloc.c:2657 > vfree+0x17e/0x890 mm/vmalloc.c:3382 > delayed_vfree_work+0x57/0x70 mm/vmalloc.c:3303 > process_one_work+0x9a2/0x1ba0 kernel/workqueue.c:3229 > process_scheduled_works kernel/workqueue.c:3310 [inline] > worker_thread+0x677/0xe90 kernel/workqueue.c:3391 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Memory state around the buggy address: > ffff888027873f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff888027873f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >ffff888027874000: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > ^ > ffff888027874080: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc > ffff888027874100: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc > ================================================================== > We also find a similar bug report in function zswap_store(), listed as below: > > ================================================================== > BUG: KASAN: slab-use-after-free in zswap_compress mm/zswap.c:925 [inline] > BUG: KASAN: slab-use-after-free in zswap_store_page mm/zswap.c:1426 [inline] > BUG: KASAN: slab-use-after-free in zswap_store+0x2307/0x25e0 mm/zswap.c:1533 > Read of size 4 at addr ffff8880219f6b44 by task kswapd0/88 > > CPU: 1 UID: 0 PID: 88 Comm: kswapd0 Tainted: G U > 6.12.0-09435-g2c22dc1ee3a1 #11 > Tainted: [U]=USER > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:94 [inline] > dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:378 [inline] > print_report+0xc0/0x5e0 mm/kasan/report.c:489 > kasan_report+0xbd/0xf0 mm/kasan/report.c:602 > zswap_compress mm/zswap.c:925 [inline] > zswap_store_page mm/zswap.c:1426 [inline] > zswap_store+0x2307/0x25e0 mm/zswap.c:1533 > swap_writepage+0x3a8/0xe50 mm/page_io.c:279 > pageout+0x3b9/0xa90 mm/vmscan.c:689 > shrink_folio_list+0x2988/0x4340 mm/vmscan.c:1367 > evict_folios+0x72b/0x1a10 mm/vmscan.c:4593 > try_to_shrink_lruvec+0x62b/0xa60 mm/vmscan.c:4789 > shrink_one+0x417/0x7c0 mm/vmscan.c:4834 > shrink_many mm/vmscan.c:4897 [inline] > lru_gen_shrink_node mm/vmscan.c:4975 [inline] > shrink_node+0x269a/0x3d60 mm/vmscan.c:5956 > kswapd_shrink_node mm/vmscan.c:6785 [inline] > balance_pgdat+0xbe5/0x18c0 mm/vmscan.c:6977 > kswapd+0x6ff/0xd60 mm/vmscan.c:7246 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > </TASK> > > Allocated by task 1: > kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 > kasan_save_track+0x14/0x30 mm/kasan/common.c:68 > poison_kmalloc_redzone mm/kasan/common.c:377 [inline] > __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 > kasan_kmalloc include/linux/kasan.h:260 [inline] > __do_kmalloc_node mm/slub.c:4283 [inline] > __kmalloc_noprof+0x212/0x530 mm/slub.c:4295 > kmalloc_noprof include/linux/slab.h:905 [inline] > kzalloc_noprof include/linux/slab.h:1037 [inline] > __acomp_request_alloc_noprof include/crypto/internal/acompress.h:75 [inline] > acomp_request_alloc+0x46/0x110 crypto/acompress.c:131 > zswap_cpu_comp_prepare+0x1f4/0x470 mm/zswap.c:840 > cpuhp_invoke_callback+0x26d/0x9d0 kernel/cpu.c:204 > cpuhp_issue_call+0x1c1/0x8d0 kernel/cpu.c:2375 > __cpuhp_state_add_instance_cpuslocked+0x26a/0x3c0 kernel/cpu.c:2437 > __cpuhp_state_add_instance+0xd7/0x2e0 kernel/cpu.c:2458 > cpuhp_state_add_instance include/linux/cpuhotplug.h:386 [inline] > zswap_pool_create+0x2c3/0x5c0 mm/zswap.c:288 > __zswap_pool_create_fallback mm/zswap.c:356 [inline] > zswap_setup+0x3a5/0x820 mm/zswap.c:1781 > zswap_init+0x2d/0x40 mm/zswap.c:1817 > do_one_initcall+0x111/0x6d0 init/main.c:1266 > do_initcall_level init/main.c:1328 [inline] > do_initcalls init/main.c:1344 [inline] > do_basic_setup init/main.c:1363 [inline] > kernel_init_freeable+0x5ae/0x8a0 init/main.c:1577 > kernel_init+0x1e/0x2d0 init/main.c:1466 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Freed by task 901: > kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 > kasan_save_track+0x14/0x30 mm/kasan/common.c:68 > kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582 > poison_slab_object mm/kasan/common.c:247 [inline] > __kasan_slab_free+0x54/0x70 mm/kasan/common.c:264 > kasan_slab_free include/linux/kasan.h:233 [inline] > slab_free_hook mm/slub.c:2338 [inline] > slab_free mm/slub.c:4598 [inline] > kfree+0x14e/0x4d0 mm/slub.c:4746 > zswap_cpu_comp_dead+0xe3/0x1c0 mm/zswap.c:874 > cpuhp_invoke_callback+0x564/0x9d0 kernel/cpu.c:216 > __cpuhp_invoke_callback_range+0x104/0x220 kernel/cpu.c:965 > cpuhp_invoke_callback_range kernel/cpu.c:989 [inline] > cpuhp_down_callbacks kernel/cpu.c:1382 [inline] > _cpu_down+0x41d/0xef0 kernel/cpu.c:1443 > __cpu_down_maps_locked+0x6f/0x90 kernel/cpu.c:1473 > work_for_cpu_fn+0x55/0xa0 kernel/workqueue.c:6719 > process_one_work+0x9a2/0x1ba0 kernel/workqueue.c:3229 > process_scheduled_works kernel/workqueue.c:3310 [inline] > worker_thread+0x677/0xe90 kernel/workqueue.c:3391 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > The buggy address belongs to the object at ffff8880219f6b00 > which belongs to the cache kmalloc-96 of size 96 > The buggy address is located 68 bytes inside of > freed 96-byte region [ffff8880219f6b00, ffff8880219f6b60) > > The buggy address belongs to the physical page: > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x219f6 > anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) > page_type: f5(slab) > raw: 00fff00000000000 ffff88801b041280 ffffea0000887d00 dead000000000005 > raw: 0000000000000000 0000000000200020 00000001f5000000 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask > 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid > 1 (swapper/0), ts 15792736110, free_ts 14433067061 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x2e7/0x350 mm/page_alloc.c:1556 > prep_new_page mm/page_alloc.c:1564 [inline] > get_page_from_freelist+0xe4e/0x2b20 mm/page_alloc.c:3474 > __alloc_pages_noprof+0x219/0x21f0 mm/page_alloc.c:4751 > alloc_pages_mpol_noprof+0x2b6/0x600 mm/mempolicy.c:2265 > alloc_slab_page mm/slub.c:2408 [inline] > allocate_slab mm/slub.c:2574 [inline] > new_slab+0x2d5/0x420 mm/slub.c:2627 > ___slab_alloc+0xbb7/0x1850 mm/slub.c:3815 > __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3905 > __slab_alloc_node mm/slub.c:3980 [inline] > slab_alloc_node mm/slub.c:4141 [inline] > __kmalloc_cache_noprof+0x280/0x410 mm/slub.c:4309 > kmalloc_noprof include/linux/slab.h:901 [inline] > kzalloc_noprof include/linux/slab.h:1037 [inline] > usb_hub_create_port_device+0xbb/0xde0 drivers/usb/core/port.c:743 > hub_configure drivers/usb/core/hub.c:1710 [inline] > hub_probe+0x1ceb/0x2fc0 drivers/usb/core/hub.c:1965 > usb_probe_interface+0x314/0x9f0 drivers/usb/core/driver.c:399 > call_driver_probe drivers/base/dd.c:579 [inline] > really_probe+0x252/0xa90 drivers/base/dd.c:658 > __driver_probe_device+0x1df/0x450 drivers/base/dd.c:800 > driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830 > __device_attach_driver+0x1db/0x2f0 drivers/base/dd.c:958 > bus_for_each_drv+0x14c/0x1d0 drivers/base/bus.c:459 > page last free pid 25 tgid 25 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1127 [inline] > free_unref_page+0x714/0x10c0 mm/page_alloc.c:2657 > vfree+0x17e/0x890 mm/vmalloc.c:3382 > delayed_vfree_work+0x57/0x70 mm/vmalloc.c:3303 > process_one_work+0x9a2/0x1ba0 kernel/workqueue.c:3229 > process_scheduled_works kernel/workqueue.c:3310 [inline] > worker_thread+0x677/0xe90 kernel/workqueue.c:3391 > kthread+0x2ca/0x3b0 kernel/kthread.c:389 > ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Memory state around the buggy address: > ffff8880219f6a00: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc > ffff8880219f6a80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc > >ffff8880219f6b00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > ^ > ffff8880219f6b80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc > ffff8880219f6c00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > ================================================================== > If you have any questions, please contact us. > > Best Regards, > Yue
