assertion failed: kref

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 93b9607ebeff Serialize printing during panic()
git tree: https://github.com/akaros/akaros.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=16bd0768400000
kernel config: https://syzkaller.appspot.com/x/.config?x=efef8cf2939304d3
dashboard link: https://syzkaller.appspot.com/bug?extid=4ea9ed2220ee4d513e0b
compiler:

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4ea9ed...@syzkaller.appspotmail.com

kernel panic at /syzkaller/managers/main/kernel/kern/include/kref.h:61,
from core 1: assertion failed: kref
Stack Backtrace on Core 1:
#01 [<0xffffffffc200a3b7>] in backtrace at src/kdebug.c:219
#02 [<0xffffffffc2009b7c>] in _panic at src/init.c:266
#03 [<0xffffffffc2049424>] in kref_get at include/kref.h:61
#04 [< [inline] >] in proc_incref.10203 at src/process.c:563
#04 [<0xffffffffc204945e>] in enum_proc.10203 at src/process.c:2346
#05 [<0xffffffffc2009151>] in hash_for_each at src/hashtable.c:427
#06 [<0xffffffffc204e8e7>] in proc_get_set at src/process.c:2367
#07 [<0xffffffffc2045c61>] in profiler_emit_current_system_status at
src/profiler.c:270
#08 [<0xffffffffc2045d83>] in profiler_setup at src/profiler.c:421
#09 [<0xffffffffc207ad5a>] in kprof_open at drivers/dev/kprof.c:228
#10 [<0xffffffffc20338e0>] in __namec_from at src/ns/chan.c:1225
#11 [<0xffffffffc20340af>] in namec at src/ns/chan.c:1509
#12 [<0xffffffffc2041566>] in sysopenat at src/ns/sysfile.c:590
#13 [<0xffffffffc205859f>] in sys_openat at src/syscall.c:1805
#14 [<0xffffffffc2059149>] in syscall at src/syscall.c:2528
#15 [<0xffffffffc2059304>] in run_local_syscall at src/syscall.c:2563
#16 [<0xffffffffc2059839>] in prep_syscalls at src/syscall.c:2583
#17 [<0xffffffffc20aaf1a>] in sysenter_callwrapper at arch/x86/trap.c:859


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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: c5f7000db927 Print backtraces when we do a warn()
git tree: https://github.com/akaros/akaros.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=16b48768400000

kernel config: https://syzkaller.appspot.com/x/.config?x=efef8cf2939304d3
dashboard link: https://syzkaller.appspot.com/bug?extid=4ea9ed2220ee4d513e0b
compiler:

syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=15c2cb2c400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1326732c400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4ea9ed...@syzkaller.appspotmail.com

kernel panic at /syzkaller/managers/main/kernel/kern/include/kref.h:61,

from core 2: assertion failed: kref
Stack Backtrace on Core 2:
#01 [<0xffffffffc200a2dc>] in backtrace at src/kdebug.c:220
#02 [<0xffffffffc2009afd>] in _panic at src/init.c:268
#03 [<0xffffffffc2049506>] in kref_get at include/kref.h:61
#04 [< [inline] >] in proc_incref.10201 at src/process.c:563
#04 [<0xffffffffc204953e>] in enum_proc.10201 at src/process.c:2346
#05 [<0xffffffffc20091a1>] in hash_for_each at src/hashtable.c:427
#06 [<0xffffffffc204ea37>] in proc_get_set at src/process.c:2367
#07 [<0xffffffffc2045c11>] in profiler_emit_current_system_status at
src/profiler.c:270
#08 [<0xffffffffc2045d33>] in profiler_setup at src/profiler.c:421
#09 [<0xffffffffc207b14a>] in kprof_open at drivers/dev/kprof.c:228
#10 [<0xffffffffc2033850>] in __namec_from at src/ns/chan.c:1232
#11 [<0xffffffffc203402f>] in namec at src/ns/chan.c:1516
#12 [<0xffffffffc20414f6>] in sysopenat at src/ns/sysfile.c:590
#13 [<0xffffffffc20588af>] in sys_openat at src/syscall.c:1805
#14 [<0xffffffffc2059459>] in syscall at src/syscall.c:2528
#15 [<0xffffffffc2059624>] in run_local_syscall at src/syscall.c:2563
#16 [<0xffffffffc2059b59>] in prep_syscalls at src/syscall.c:2583
#17 [<0xffffffffc20ab41a>] in sysenter_callwrapper at arch/x86/trap.c:854