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/trace/events/vmalloc.h | 123 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 include/trace/events/vmalloc.h (limited to 'include/trace/events/vmalloc.h') diff --git a/include/trace/events/vmalloc.h b/include/trace/events/vmalloc.h new file mode 100644 index 000000000..ad4e02191 --- /dev/null +++ b/include/trace/events/vmalloc.h @@ -0,0 +1,123 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM vmalloc + +#if !defined(_TRACE_VMALLOC_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_VMALLOC_H + +#include + +/** + * alloc_vmap_area - called when a new vmap allocation occurs + * @addr: an allocated address + * @size: a requested size + * @align: a requested alignment + * @vstart: a requested start range + * @vend: a requested end range + * @failed: an allocation failed or not + * + * This event is used for a debug purpose, it can give an extra + * information for a developer about how often it occurs and which + * parameters are passed for further validation. + */ +TRACE_EVENT(alloc_vmap_area, + + TP_PROTO(unsigned long addr, unsigned long size, unsigned long align, + unsigned long vstart, unsigned long vend, int failed), + + TP_ARGS(addr, size, align, vstart, vend, failed), + + TP_STRUCT__entry( + __field(unsigned long, addr) + __field(unsigned long, size) + __field(unsigned long, align) + __field(unsigned long, vstart) + __field(unsigned long, vend) + __field(int, failed) + ), + + TP_fast_assign( + __entry->addr = addr; + __entry->size = size; + __entry->align = align; + __entry->vstart = vstart; + __entry->vend = vend; + __entry->failed = failed; + ), + + TP_printk("va_start: %lu size=%lu align=%lu vstart=0x%lx vend=0x%lx failed=%d", + __entry->addr, __entry->size, __entry->align, + __entry->vstart, __entry->vend, __entry->failed) +); + +/** + * purge_vmap_area_lazy - called when vmap areas were lazily freed + * @start: purging start address + * @end: purging end address + * @npurged: numbed of purged vmap areas + * + * This event is used for a debug purpose. It gives some + * indication about start:end range and how many objects + * are released. + */ +TRACE_EVENT(purge_vmap_area_lazy, + + TP_PROTO(unsigned long start, unsigned long end, + unsigned int npurged), + + TP_ARGS(start, end, npurged), + + TP_STRUCT__entry( + __field(unsigned long, start) + __field(unsigned long, end) + __field(unsigned int, npurged) + ), + + TP_fast_assign( + __entry->start = start; + __entry->end = end; + __entry->npurged = npurged; + ), + + TP_printk("start=0x%lx end=0x%lx num_purged=%u", + __entry->start, __entry->end, __entry->npurged) +); + +/** + * free_vmap_area_noflush - called when a vmap area is freed + * @va_start: a start address of VA + * @nr_lazy: number of current lazy pages + * @nr_lazy_max: number of maximum lazy pages + * + * This event is used for a debug purpose. It gives some + * indication about a VA that is released, number of current + * outstanding areas and a maximum allowed threshold before + * dropping all of them. + */ +TRACE_EVENT(free_vmap_area_noflush, + + TP_PROTO(unsigned long va_start, unsigned long nr_lazy, + unsigned long nr_lazy_max), + + TP_ARGS(va_start, nr_lazy, nr_lazy_max), + + TP_STRUCT__entry( + __field(unsigned long, va_start) + __field(unsigned long, nr_lazy) + __field(unsigned long, nr_lazy_max) + ), + + TP_fast_assign( + __entry->va_start = va_start; + __entry->nr_lazy = nr_lazy; + __entry->nr_lazy_max = nr_lazy_max; + ), + + TP_printk("va_start=0x%lx nr_lazy=%lu nr_lazy_max=%lu", + __entry->va_start, __entry->nr_lazy, __entry->nr_lazy_max) +); + +#endif /* _TRACE_VMALLOC_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1