Dear kernel developers, I was trying to debug the crash - memory leak in hwsim_add_one [1] recently. However, I encountered a disgusting issue: my breakpoint and printk/pr_alert in the functions that will be surely executed do not work. The stack trace is in the following. I wrote this email to ask for some suggestions on how to debug such cases? Thanks very much. Looking forward to your reply. [<ffffffff82b09f12>] kmalloc include/linux/slab.h:556 [inline] [<ffffffff82b09f12>] kzalloc include/linux/slab.h:686 [inline] [<ffffffff82b09f12>] hwsim_alloc_edge.constprop.0+0x22/0x80 drivers/net/ieee802154/mac802154_hwsim.c:385 [<ffffffff82b0b0f3>] hwsim_subscribe_all_others drivers/net/ieee802154/mac802154_hwsim.c:709 [inline] [<ffffffff82b0b0f3>] hwsim_add_one+0x3b3/0x640 drivers/net/ieee802154/mac802154_hwsim.c:802 [<ffffffff82b0b3c4>] hwsim_probe+0x44/0xd0 drivers/net/ieee802154/mac802154_hwsim.c:848 [<ffffffff82628bf1>] platform_probe+0x81/0x120 drivers/base/platform.c:1447 [<ffffffff82625679>] really_probe+0x159/0x500 drivers/base/dd.c:576 [<ffffffff82625aab>] driver_probe_device+0x8b/0x100 drivers/base/dd.c:763 [<ffffffff82626325>] device_driver_attach+0x105/0x110 drivers/base/dd.c:1039 [<ffffffff826263d1>] __driver_attach drivers/base/dd.c:1117 [inline] [<ffffffff826263d1>] __driver_attach+0xa1/0x140 drivers/base/dd.c:1070 [<ffffffff82622459>] bus_for_each_dev+0xa9/0x100 drivers/base/bus.c:305 [<ffffffff826244e0>] bus_add_driver+0x160/0x280 drivers/base/bus.c:622 [<ffffffff82627233>] driver_register+0xc3/0x150 drivers/base/driver.c:171 [<ffffffff874fa3dc>] hwsim_init_module+0xae/0x107 drivers/net/ieee802154/mac802154_hwsim.c:899 [<ffffffff81001083>] do_one_initcall+0x63/0x2e0 init/main.c:1249 [<ffffffff87489873>] do_initcall_level init/main.c:1322 [inline] [<ffffffff87489873>] do_initcalls init/main.c:1338 [inline] [<ffffffff87489873>] do_basic_setup init/main.c:1358 [inline] [<ffffffff87489873>] kernel_init_freeable+0x1f4/0x26e init/main.c:1560 [<ffffffff84359255>] kernel_init+0xc/0x1a7 init/main.c:1447 [<ffffffff810022ef>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 [1] https://groups.google.com/g/syzkaller-bugs/c/iEEZ_UOvoEY/m/6sm4bt6EAgAJ -- My best regards to you. No System Is Safe! Dongliang Mu
