From 4310c6b8e75d6a47f7548e5948fbe6318aa4440a Mon Sep 17 00:00:00 2001 From: Fedor Pchelkin Date: Mon, 31 Aug 2026 10:58:09 +0300 Subject: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool. Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") Cc: stable@vger.kernel.org Signed-off-by: Fedor Pchelkin Signed-off-by: Mika Westerberg --- include/asm-generic/vdso/clocksource.h | 0 include/asm-generic/vdso/vsyscall.h | 35 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+) create mode 100644 include/asm-generic/vdso/clocksource.h create mode 100644 include/asm-generic/vdso/vsyscall.h (limited to 'include/asm-generic/vdso') diff --git a/include/asm-generic/vdso/clocksource.h b/include/asm-generic/vdso/clocksource.h new file mode 100644 index 000000000..e69de29bb diff --git a/include/asm-generic/vdso/vsyscall.h b/include/asm-generic/vdso/vsyscall.h new file mode 100644 index 000000000..a6b03cfba --- /dev/null +++ b/include/asm-generic/vdso/vsyscall.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_VSYSCALL_H +#define __ASM_GENERIC_VSYSCALL_H + +#ifndef __ASSEMBLER__ + +#ifndef __arch_get_vdso_u_time_data +static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void) +{ + return &vdso_u_time_data; +} +#endif + +#ifndef __arch_get_vdso_u_rng_data +static __always_inline const struct vdso_rng_data *__arch_get_vdso_u_rng_data(void) +{ + return &vdso_u_rng_data; +} +#endif + +#ifndef __arch_update_vdso_clock +static __always_inline void __arch_update_vdso_clock(struct vdso_clock *vc) +{ +} +#endif /* __arch_update_vdso_clock */ + +#ifndef __arch_sync_vdso_time_data +static __always_inline void __arch_sync_vdso_time_data(struct vdso_time_data *vdata) +{ +} +#endif /* __arch_sync_vdso_time_data */ + +#endif /* !__ASSEMBLER__ */ + +#endif /* __ASM_GENERIC_VSYSCALL_H */ -- cgit v1.3.1