core: redirect LSan's report to /dev/console during manager exit
When exiting PID 1 we most likely don't have stdio/stdout open, so the
final LSan check would not print any actionable information and would
just crash PID 1 leading up to a kernel panic, which is a bit annoying.
Let's instead attempt to open /dev/console, and if we succeed redirect
LSan's report there.
The result is a bit messy, as it's slightly interleaved with the kernel
panic, but it's definitely better than not having the stack trace at
all:
[ OK ] Reached target final.target.
[ OK ] Finished systemd-poweroff.service.
[ OK ] Reached target poweroff.target.
=================================================================
3 1m 43.251782] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100
[ 43.252838] CPU: 2 PID: 1 Comm: systemd Not tainted 6.4.12-200.fc38.x86_64 #1
==[1==ERR O R :4 3Le.a2k53562] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014
[ 43.254683] Call Trace:
[ 43.254911] <TASK>
[ 43.255107] dump_stack_lvl+0x47/0x60
S[ a 43.n2555i05] panic+t0x192/0x350
izer[ :43.255966 ] do_exit+0x990/0xdb10
etec[ 43.256504] do_group_exit+0x31/0x80
[ 43.256889] __x64_sys_exit_group+0x18/0x20
[ 43.257288] do_syscall_64+0x60/0x90
o_user_mod leaks[ 43.257618] ? syscall_exit_t
+0x2b/0x40
[ 43.258411] ? do_syscall_64+0x6c/0x90
1mDirect le[ 43.258755] ak of 21 byte(s)? exc_page_fault+0x7f/0x180
[ 43.259446] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[ 43.259901] RiIP: 0033:0x7f357nb8f3ad4
1 objec[ 43.260354] Ctode: 48 89 (f7 0f 05 c3 sf3 0f 1e fa b8 3b 00 00 00) 0f 05 c3 0f 1f 4 0 00 f3 0f 1e fa 50 58 b8 e7 00 00 00 48 83 ec 08 48 63 ff 0f 051
[ 43.262581] RSP: 002b:
00007ffc25872440 EFLAGS:
00000202 ORIG_RAX:
00000000000000e7
a RBX:
00007f357be9b218 RCX: 00007f357b8f3ad4m:ffd
[ 43.264512] RDX:
0000000000000001 RSI:
00007f357b933b63 RDI:
0000000000000001
[ 43.265355] RBP:
00007f357be9b218 R08:
efffffffffffffff R09:
00007ffc258721ef
[ 43.266191] R10:
000000000000003f R11:
0000000000000202 R12:
00000fe6ae9e0000
[ 43.266891] R13:
00007f3574f00000 R14:
0000000000000000 R15:
0000000000000007
[ 43.267517] </TASK>
#0 0x7f357b8814a8 in strdup (/lib64/libasan.so.8+0x814a8) (BuildId:
e5f0a0d511a659fbc47bf41072869139cb2db47f)
#1 0x7f3578d43317 in cg_path_decode_unit ../src/basic/cgroup-util.c:1132
#2 0x7f3578d43936 in cg_path_get_unit ../src/basic/cgroup-util.c:1190
#3 0x7f3578d440f6 in cg_pid_get_unit ../src/basic/cgroup-util.c:1234
#4 0x7f35789263d7 in bus_log_caller ../src/shared/bus-util.c:734
#5 0x7f357a9cf10a in method_reload ../src/core/dbus-manager.c:1621
#6 0x7f3578f77497 in method_callbacks_run ../src/libsystemd/sd-bus/bus-objects.c:406
#7 0x7f3578f80dd8 in object_find_and_run ../src/libsystemd/sd-bus/bus-objects.c:1319
#8 0x7f3578f82487 in bus_process_object ../src/libsystemd/sd-bus/bus-objects.c:1439
#9 0x7f3578fe41f1 in process_message ../src/libsystemd/sd-bus/sd-bus.c:3007
#10 0x7f3578fe477b in process_running ../src/libsystemd/sd-bus/sd-bus.c:3049
#11 0x7f3578fe75d1 in bus_process_internal ../src/libsystemd/sd-bus/sd-bus.c:3269
#12 0x7f3578fe776e in sd_bus_process ../src/libsystemd/sd-bus/sd-bus.c:3296
#13 0x7f3578feaedc in io_callback ../src/libsystemd/sd-bus/sd-bus.c:3638
#14 0x7f35791c2f68 in source_dispatch ../src/libsystemd/sd-event/sd-event.c:4187
#15 0x7f35791cc6f9 in sd_event_dispatch ../src/libsystemd/sd-event/sd-event.c:4808
#16 0x7f35791cd830 in sd_event_run ../src/libsystemd/sd-event/sd-event.c:4869
#17 0x7f357abcd572 in manager_loop ../src/core/manager.c:3244
#18 0x41db21 in invoke_main_loop ../src/core/main.c:1960
#19 0x426615 in main ../src/core/main.c:3125
#20 0x7f3577c49b49 in __libc_start_call_main (/lib64/libc.so.6+0x27b49) (BuildId:
245240a31888ad5c11bbc55b18e02d87388f59a9)
#21 0x7f3577c49c0a in __libc_start_main_alias_2 (/lib64/libc.so.6+0x27c0a) (BuildId:
245240a31888ad5c11bbc55b18e02d87388f59a9)
#22 0x408494 in _start (/usr/lib/systemd/systemd+0x408494) (BuildId:
fe61e1b0f00b6a36aa34e707a98c15c52f6b960a)
SUMMARY: AddressSanitizer: 21 byte(s) leaked in 1 allocation(s).
[ 43.295912] Kernel Offset: 0x7000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 43.297036] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100 ]---
Originally noticed in https://github.com/systemd/systemd/pull/28579.