On Sat, 4 Sept 2021 at 13:57, syzbot <syzbot+488ddf8087564d6de6e2@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: f1583cb1be35 Merge tag 'linux-kselftest-next-5.15-rc1' of .. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=16354043300000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5fe535c85e8d7384 > dashboard link: https://syzkaller.appspot.com/bug?extid=488ddf8087564d6de6e2 > compiler: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 > userspace arch: arm64 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+488ddf8087564d6de6e2@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: invalid-access in __entry_tramp_text_end+0xdfc/0x3000 > Read at addr f4ff000002a361a0 by task kdevtmpfs/22 > Pointer tag: [f4], memory tag: [fe] > > CPU: 1 PID: 22 Comm: kdevtmpfs Not tainted 5.14.0-syzkaller-09284-gf1583cb1be35 #0 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0x0/0x1ac arch/arm64/kernel/stacktrace.c:76 > show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:215 > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0x68/0x84 lib/dump_stack.c:105 > print_address_description+0x7c/0x2b4 mm/kasan/report.c:256 > __kasan_report mm/kasan/report.c:442 [inline] > kasan_report+0x134/0x380 mm/kasan/report.c:459 > __do_kernel_fault+0x128/0x1bc arch/arm64/mm/fault.c:317 > do_bad_area arch/arm64/mm/fault.c:466 [inline] > do_tag_check_fault+0x74/0x90 arch/arm64/mm/fault.c:737 > do_mem_abort+0x44/0xb4 arch/arm64/mm/fault.c:813 > el1_abort+0x40/0x60 arch/arm64/kernel/entry-common.c:357 > el1h_64_sync_handler+0xb0/0xd0 arch/arm64/kernel/entry-common.c:408 > el1h_64_sync+0x78/0x7c arch/arm64/kernel/entry.S:567 > __entry_tramp_text_end+0xdfc/0x3000 /\/\/\/\/\/\/\ This is broken unwind on arm64. d_lookup statically calls __d_lookup, not __entry_tramp_text_end (which is not even a function). See the following thread for some debugging details: https://lore.kernel.org/lkml/CACT4Y+ZByJ71QfYHTByWaeCqZFxYfp8W8oyrK0baNaSJMDzoUw@xxxxxxxxxxxxxx/ But there is also the use-after-free in d_lookup. > d_lookup+0x44/0x70 fs/dcache.c:2370 > lookup_dcache+0x24/0x84 fs/namei.c:1520 > __lookup_hash+0x24/0xd0 fs/namei.c:1543 > kern_path_locked+0x90/0x10c fs/namei.c:2567 > handle_remove+0x38/0x284 drivers/base/devtmpfs.c:312 > handle drivers/base/devtmpfs.c:382 [inline] > devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] > devtmpfsd+0x8c/0xd0 drivers/base/devtmpfs.c:437 > kthread+0x150/0x15c kernel/kthread.c:319 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:756 > > Allocated by task 22: > kasan_save_stack+0x28/0x60 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+0xb0/0x110 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+0x1cc/0x340 mm/slub.c:2972 > getname_kernel+0x30/0x150 fs/namei.c:226 > kern_path_locked+0x2c/0x10c fs/namei.c:2558 > handle_remove+0x38/0x284 drivers/base/devtmpfs.c:312 > handle drivers/base/devtmpfs.c:382 [inline] > devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] > devtmpfsd+0x8c/0xd0 drivers/base/devtmpfs.c:437 > kthread+0x150/0x15c kernel/kthread.c:319 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:756 > > Freed by task 22: > kasan_save_stack+0x28/0x60 mm/kasan/common.c:38 > kasan_set_track+0x28/0x3c mm/kasan/common.c:46 > kasan_set_free_info+0x20/0x30 mm/kasan/tags.c:36 > ____kasan_slab_free.constprop.0+0x178/0x1e0 mm/kasan/common.c:366 > __kasan_slab_free+0x10/0x1c 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+0xc4/0x20c mm/slub.c:1653 > slab_free mm/slub.c:3213 [inline] > kmem_cache_free+0x9c/0x420 mm/slub.c:3229 > putname.part.0+0x68/0x7c fs/namei.c:270 > putname include/linux/err.h:41 [inline] > filename_parentat fs/namei.c:2547 [inline] > kern_path_locked+0x64/0x10c fs/namei.c:2558 > handle_remove+0x38/0x284 drivers/base/devtmpfs.c:312 > handle drivers/base/devtmpfs.c:382 [inline] > devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] > devtmpfsd+0x8c/0xd0 drivers/base/devtmpfs.c:437 > kthread+0x150/0x15c kernel/kthread.c:319 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:756 > > The buggy address belongs to the object at ffff000002a36180 > which belongs to the cache names_cache of size 4096 > The buggy address is located 32 bytes inside of > 4096-byte region [ffff000002a36180, ffff000002a37180) > The buggy address belongs to the page: > page:00000000a105b3ae refcount:1 mapcount:0 mapping:0000000000000000 index:0xf3ff000002a34100 pfn:0x42a30 > head:00000000a105b3ae order:3 compound_mapcount:0 compound_pincount:0 > flags: 0x1ffc00000010200(slab|head|node=0|zone=0|lastcpupid=0x7ff|kasantag=0x0) > raw: 01ffc00000010200 0000000000000000 dead000000000122 faff000002837700 > raw: f3ff000002a34100 0000000080070003 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff000002a35f00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe > ffff000002a36000: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe > >ffff000002a36100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe > ^ > ffff000002a36200: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe > ffff000002a36300: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000a3cf8605cb2a1ec0%40google.com.
