syzbot


WARNING: suspicious RCU usage in mas_state_walk (2)

Status: auto-obsoleted due to no activity on 2023/06/30 05:34
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+a5ca677fb59b73010889@syzkaller.appspotmail.com
First crash: 491d, last: 470d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] WARNING: suspicious RCU usage in mas_state_walk (2) 0 (1) 2023/02/13 06:16
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: suspicious RCU usage in mas_state_walk maple-tree C 2 492d 492d 0/27 closed as invalid on 2023/02/08 16:28
Last patch testing requests (2)
Created Duration User Patch Repo Result
2023/05/14 10:09 24m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci OK log
2023/05/14 10:09 24m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci OK log

Sample crash report:
=============================
WARNING: suspicious RCU usage
6.2.0-syzkaller-18300-g2ebd1fbb946d #0 Not tainted
-----------------------------
lib/maple_tree.c:852 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
5 locks held by syz-executor179/6429:
 #0: ffff0000d8dc0460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x244/0x914 fs/read_write.c:580
 #1: ffff0000d2f28088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c8/0x48c fs/kernfs/file.c:325
 #2: ffff0000c110ecb8 (kn->active#42){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1e4/0x48c fs/kernfs/file.c:326
 #3: ffff800015e40b88 (ksm_thread_mutex){+.+.}-{3:3}, at: run_store+0x10c/0xa1c mm/ksm.c:2954
 #4: ffff0000cd695f88 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
 #4: ffff0000cd695f88 (&mm->mmap_lock){++++}-{3:3}, at: unmerge_and_remove_all_rmap_items mm/ksm.c:990 [inline]
 #4: ffff0000cd695f88 (&mm->mmap_lock){++++}-{3:3}, at: run_store+0x274/0xa1c mm/ksm.c:2960

stack backtrace:
CPU: 1 PID: 6429 Comm: syz-executor179 Not tainted 6.2.0-syzkaller-18300-g2ebd1fbb946d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 dump_stack+0x1c/0x28 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x188/0x1e0 kernel/locking/lockdep.c:6597
 mas_root lib/maple_tree.c:852 [inline]
 mas_start lib/maple_tree.c:1357 [inline]
 mas_state_walk+0x2ac/0x400 lib/maple_tree.c:3838
 mas_walk+0x44/0x148 lib/maple_tree.c:5046
 mas_find+0x1bc/0x200 lib/maple_tree.c:6012
 vma_find include/linux/mm.h:674 [inline]
 vma_next include/linux/mm.h:683 [inline]
 unmerge_and_remove_all_rmap_items mm/ksm.c:991 [inline]
 run_store+0x28c/0xa1c mm/ksm.c:2960
 kobj_attr_store+0x6c/0x90 lib/kobject.c:824
 sysfs_kf_write+0x200/0x280 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x610/0x914 fs/read_write.c:584
 ksys_write+0x15c/0x26c fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/02/27 16:40 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2ebd1fbb946d e792ae78 .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/09 07:37 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci eaed33698e35 14a312c8 .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/21 10:22 upstream 89f5349e0673 f949448d .config console log report info ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in mas_state_walk
2023/02/20 01:53 upstream c9c3395d5e3d bcdf85f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in mas_state_walk
2023/02/18 10:35 upstream dbeed98d89ea d02e9a70 .config console log report info ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in mas_state_walk
2023/02/15 07:06 upstream e1c04510f521 1d6b4af7 .config console log report info ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in mas_state_walk
2023/02/13 15:14 upstream ceaa837f96ad 4d66ad72 .config console log report info ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in mas_state_walk
2023/03/02 05:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2ebd1fbb946d f8902b57 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/27 09:51 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2ebd1fbb946d e792ae78 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/22 12:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a9b06ec42c0f 409945bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/21 09:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a9b06ec42c0f f949448d .config console log report info ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/17 12:02 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2d3827b3f393 3e7039f4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/16 12:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2d3827b3f393 7338e3c4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/15 11:16 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2d3827b3f393 6be0f1f5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/13 12:06 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2d3827b3f393 4d66ad72 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/10 19:29 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2d3827b3f393 95871dcc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/09 17:17 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci eaed33698e35 07980f9d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
2023/02/09 06:04 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci eaed33698e35 14a312c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: suspicious RCU usage in mas_state_walk
* Struck through repros no longer work on HEAD.