bisecting fixing commit since e68061375f792af245fefbc13e3e078fa92d3539 building syzkaller on 52e3731913ab2677be27c29ed8142b04e8f28521 testing commit e68061375f792af245fefbc13e3e078fa92d3539 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 7655392819de5033a383aec477f58329f9b02d8cdce0e2c0917fc7a6ec53fdbe run #0: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #1: crashed: INFO: rcu detected stall in smp_call_function run #2: crashed: INFO: rcu detected stall in addrconf_rs_timer run #3: crashed: INFO: rcu detected stall in batadv_iv_send_outstanding_bat_ogm_packet run #4: crashed: INFO: rcu detected stall in corrupted run #5: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #6: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #7: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #8: crashed: INFO: rcu detected stall in corrupted run #9: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #10: crashed: INFO: rcu detected stall in ipv6_list_rcv run #11: crashed: INFO: rcu detected stall in kernfs_fop_open run #12: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #13: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #14: crashed: BUG: soft lockup in mac80211_hwsim_beacon run #15: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #16: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #17: crashed: INFO: rcu detected stall in ieee80211_iface_work run #18: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #19: crashed: INFO: rcu detected stall in batadv_nc_worker testing current HEAD 4a3bb4200a5958d76cc26ebe4db4257efa56812b testing commit 4a3bb4200a5958d76cc26ebe4db4257efa56812b compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 96a4e69ebb2634faacc0b181a8b4f272af8412e3af55d43c3001692666e49a76 run #0: crashed: KASAN: use-after-free Read in __d_alloc run #1: crashed: KASAN: use-after-free Read in __d_alloc run #2: crashed: KASAN: use-after-free Read in __d_alloc run #3: crashed: KASAN: use-after-free Read in __d_alloc run #4: crashed: KASAN: use-after-free Read in __d_alloc run #5: crashed: KASAN: use-after-free Read in __d_alloc run #6: crashed: KASAN: use-after-free Read in __d_alloc run #7: crashed: KASAN: use-after-free Read in __d_alloc run #8: OK run #9: OK revisions tested: 2, total time: 31m15.939272023s (build: 10m58.945923565s, test: 19m41.502324163s) the crash still happens on HEAD commit msg: Merge tag 'dma-mapping-5.15' of git://git.infradead.org/users/hch/dma-mapping crash: KASAN: use-after-free Read in __d_alloc ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline] BUG: KASAN: use-after-free in __d_alloc+0x161/0x950 fs/dcache.c:1775 Read of size 5 at addr ffff888040974420 by task kdevtmpfs/21 CPU: 1 PID: 21 Comm: kdevtmpfs Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x45/0x59 lib/dump_stack.c:105 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:436 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 memcpy+0x20/0x60 mm/kasan/shadow.c:65 memcpy include/linux/fortify-string.h:191 [inline] __d_alloc+0x161/0x950 fs/dcache.c:1775 d_alloc+0x3f/0x200 fs/dcache.c:1823 __lookup_hash+0x97/0x140 fs/namei.c:1554 kern_path_locked+0x146/0x300 fs/namei.c:2567 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 21: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x61/0x80 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:2959 [inline] slab_alloc mm/slub.c:2967 [inline] kmem_cache_alloc+0x25b/0x480 mm/slub.c:2972 getname_kernel+0x48/0x330 fs/namei.c:226 kern_path_locked+0x6f/0x300 fs/namei.c:2558 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 21: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xe0/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1628 [inline] slab_free_freelist_hook+0xa1/0x180 mm/slub.c:1653 slab_free mm/slub.c:3213 [inline] kmem_cache_free+0x8b/0x590 mm/slub.c:3229 putname include/linux/err.h:41 [inline] filename_parentat fs/namei.c:2547 [inline] kern_path_locked+0xa7/0x300 fs/namei.c:2558 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff888040974400 which belongs to the cache names_cache of size 4096 The buggy address is located 32 bytes inside of 4096-byte region [ffff888040974400, ffff888040975400) The buggy address belongs to the page: page:00000000c0e0aca5 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40970 head:00000000c0e0aca5 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff88800f1c43c0 raw: 0000000000000000 0000000080070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888040974300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888040974380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888040974400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888040974480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888040974500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================