Greetings,
Ran into the following issue today. It's sort of interesting, not sure
what even to do about it. The
uart -> tty -> mm /* kmalloc -> kmemleak */
chain looks problematic, it certainly overlaps with
mm -> printk -> uart /* which can kmalloc and re-enter mm -> kmemleak? */
chain.
[ 40.056844] ======================================================
[ 40.056845] WARNING: possible circular locking dependency detected
[ 40.056847] 6.11.0-next-20240925+ #729 Tainted: G W N
[ 40.056849] ------------------------------------------------------
[ 40.056850] modprobe/431 is trying to acquire lock:
[ 40.056851] ffffffff83cef3e0 (console_owner){-...}-{0:0}, at: console_flush_all+0xd9/0x9d0
[ 40.056859]
[ 40.056859] but task is already holding lock:
[ 40.056859] ffffffff83ed97d8 (kmemleak_lock){-.-.}-{2:2}, at: kmemleak_free+0x2e/0x70
[ 40.056866]
[ 40.056866] which lock already depends on the new lock.
[ 40.056866]
[ 40.056867]
[ 40.056867] the existing dependency chain (in reverse order) is:
[ 40.056868]
[ 40.056868] -> #2 (kmemleak_lock){-.-.}-{2:2}:
[ 40.056872] _raw_spin_lock_irqsave+0x76/0xb0
[ 40.056876] __create_object+0x3a/0x110
[ 40.056878] __kmalloc_noprof+0x1ff/0x390
[ 40.056882] __tty_buffer_request_room+0x18b/0x4e0
[ 40.056887] __tty_insert_flip_string_flags+0x8b/0x3c0
[ 40.056889] uart_insert_char+0x211/0x7f0
[ 40.056893] serial8250_handle_irq+0x34a/0xb10
[ 40.056897] serial8250_default_handle_irq+0xaa/0x170
[ 40.056900] serial8250_interrupt+0xa7/0x130
[ 40.056902] __handle_irq_event_percpu+0x1e1/0x680
[ 40.056904] handle_irq_event+0x87/0x1c0
[ 40.056906] handle_edge_irq+0x201/0x9b0
[ 40.056910] __common_interrupt+0xb4/0x120
[ 40.056914] common_interrupt+0x78/0x90
[ 40.056917] asm_common_interrupt+0x22/0x40
[ 40.056921] default_idle+0xb/0x10
[ 40.056924] default_idle_call+0x6e/0xa0
[ 40.056927] do_idle+0x172/0x3c0
[ 40.056930] cpu_startup_entry+0x45/0x60
[ 40.056932] start_secondary+0x12b/0x130
[ 40.056935] common_startup_64+0x12c/0x137
[ 40.056938]
[ 40.056938] -> #1 (&port_lock_key){-.-.}-{2:2}:
[ 40.056942] _raw_spin_lock_irqsave+0x76/0xb0
[ 40.056945] serial8250_console_write+0xf5/0x1b10
[ 40.056947] console_flush_all+0x4fd/0x9d0
[ 40.056949] console_unlock+0x99/0x230
[ 40.056952] vprintk_emit+0x3b6/0x650
[ 40.056955] _printk+0x59/0x7b
[ 40.056958] register_console+0x7fb/0xb40
[ 40.056960] univ8250_console_init+0x3b/0x6b
[ 40.056965] console_init+0x11a/0x3bb
[ 40.056970] start_kernel+0x22a/0x39b
[ 40.056975] x86_64_start_reservations+0x26/0x2b
[ 40.056979] copy_bootdata+0x0/0xb0
[ 40.056981] common_startup_64+0x12c/0x137
[ 40.056983]
[ 40.056983] -> #0 (console_owner){-...}-{0:0}:
[ 40.056986] __lock_acquire+0x3790/0x7830
[ 40.056992] lock_acquire+0x140/0x3b0
[ 40.056994] console_flush_all+0x482/0x9d0
[ 40.056996] console_unlock+0x99/0x230
[ 40.056999] vprintk_emit+0x3b6/0x650
[ 40.057001] _printk+0x59/0x7b
[ 40.057003] __find_and_remove_object+0x106/0x120
[ 40.057005] kmemleak_free+0x3d/0x70
[ 40.057007] free_large_kmalloc+0x4d/0xb0
[ 40.057009] init_module+0x12/0xffb [zram]
[ 40.057016] do_one_initcall+0x130/0x450
[ 40.057018] do_init_module+0x36a/0x890
[ 40.057021] __se_sys_finit_module+0x513/0x7e0
[ 40.057022] do_syscall_64+0x71/0x110
[ 40.057024] entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 40.057027]
[ 40.057027] other info that might help us debug this:
[ 40.057027]
[ 40.057028] Chain exists of:
[ 40.057028] console_owner --> &port_lock_key --> kmemleak_lock
[ 40.057028]
[ 40.057032] Possible unsafe locking scenario:
[ 40.057032]
[ 40.057033] CPU0 CPU1
[ 40.057033] ---- ----
[ 40.057034] lock(kmemleak_lock);
[ 40.057035] lock(&port_lock_key);
[ 40.057037] lock(kmemleak_lock);
[ 40.057039] lock(console_owner);
[ 40.057040]
[ 40.057040] *** DEADLOCK ***
[ 40.057040]
[ 40.057041] 3 locks held by modprobe/431:
[ 40.057043] #0: ffffffff83ed97d8 (kmemleak_lock){-.-.}-{2:2}, at: kmemleak_free+0x2e/0x70
[ 40.057048] #1: ffffffff83cef440 (console_lock){+.+.}-{0:0}, at: _printk+0x59/0x7b
[ 40.057053] #2: ffffffff83cef050 (console_srcu){....}-{0:0}, at: console_flush_all+0xd9/0x9d0
[ 40.057057]
[ 40.057057] stack backtrace:
[ 40.057059] CPU: 11 UID: 0 PID: 431 Comm: modprobe Tainted: G W N 6.11.0-next-20240925+ #729
[ 40.057063] Tainted: [W]=WARN, [N]=TEST
[ 40.057065] Call Trace:
[ 40.057066] <TASK>
[ 40.057067] dump_stack_lvl+0xa3/0xeb
[ 40.057071] print_circular_bug+0x136/0x1b0
[ 40.057074] check_noncircular+0x26a/0x370
[ 40.057078] __lock_acquire+0x3790/0x7830
[ 40.057085] lock_acquire+0x140/0x3b0
[ 40.057087] ? console_flush_all+0xd9/0x9d0
[ 40.057090] ? console_flush_all+0xd9/0x9d0
[ 40.057092] console_flush_all+0x482/0x9d0
[ 40.057094] ? console_flush_all+0xd9/0x9d0
[ 40.057096] ? console_flush_all+0xd9/0x9d0
[ 40.057100] console_unlock+0x99/0x230
[ 40.057103] vprintk_emit+0x3b6/0x650
[ 40.057107] _printk+0x59/0x7b
[ 40.057110] __find_and_remove_object+0x106/0x120
[ 40.057113] kmemleak_free+0x3d/0x70
[ 40.057115] free_large_kmalloc+0x4d/0xb0
[ 40.057118] init_module+0x12/0xffb [zram]
[ 40.057125] do_one_initcall+0x130/0x450
[ 40.057127] ? __cfi_init_module+0x5/0x5 [zram]
[ 40.057133] ? stack_depot_save_flags+0x25/0x700
[ 40.057136] ? stack_trace_save+0xb3/0x150
[ 40.057140] ? kasan_save_track+0x3c/0x60
[ 40.057143] ? kasan_save_track+0x2b/0x60
[ 40.057145] ? __kasan_kmalloc+0x6e/0x80
[ 40.057147] ? do_init_module+0x16e/0x890
[ 40.057149] ? __se_sys_finit_module+0x513/0x7e0
[ 40.057151] ? do_syscall_64+0x71/0x110
[ 40.057156] ? entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 40.057160] ? stack_depot_save_flags+0x25/0x700
[ 40.057162] ? stack_trace_save+0xb3/0x150
[ 40.057165] ? __create_object+0x62/0x110
[ 40.057168] ? do_raw_spin_unlock+0x5a/0x950
[ 40.057170] ? __create_object+0x62/0x110
[ 40.057173] ? _raw_spin_unlock_irqrestore+0x31/0x40
[ 40.057176] ? __create_object+0x62/0x110
[ 40.057179] ? kasan_unpoison+0x49/0x70
[ 40.057182] ? __asan_register_globals+0x54/0x70
[ 40.057184] do_init_module+0x36a/0x890
[ 40.057189] __se_sys_finit_module+0x513/0x7e0
[ 40.057195] do_syscall_64+0x71/0x110
[ 40.057197] entry_SYSCALL_64_after_hwframe+0x4b/0x53
