From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/trace/events/module.h | 134 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 include/trace/events/module.h (limited to 'include/trace/events/module.h') diff --git a/include/trace/events/module.h b/include/trace/events/module.h new file mode 100644 index 000000000..e5a006be9 --- /dev/null +++ b/include/trace/events/module.h @@ -0,0 +1,134 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Because linux/module.h has tracepoints in the header, and ftrace.h + * used to include this file, define_trace.h includes linux/module.h + * But we do not want the module.h to override the TRACE_SYSTEM macro + * variable that define_trace.h is processing, so we only set it + * when module events are being processed, which would happen when + * CREATE_TRACE_POINTS is defined. + */ +#ifdef CREATE_TRACE_POINTS +#undef TRACE_SYSTEM +#define TRACE_SYSTEM module +#endif + +#if !defined(_TRACE_MODULE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_MODULE_H + +#include + +#ifdef CONFIG_MODULES + +struct module; + +#define show_module_flags(flags) __print_flags(flags, "", \ + { (1UL << TAINT_PROPRIETARY_MODULE), "P" }, \ + { (1UL << TAINT_OOT_MODULE), "O" }, \ + { (1UL << TAINT_FORCED_MODULE), "F" }, \ + { (1UL << TAINT_CRAP), "C" }, \ + { (1UL << TAINT_UNSIGNED_MODULE), "E" }) + +TRACE_EVENT(module_load, + + TP_PROTO(struct module *mod), + + TP_ARGS(mod), + + TP_STRUCT__entry( + __field( unsigned int, taints ) + __string( name, mod->name ) + ), + + TP_fast_assign( + __entry->taints = mod->taints; + __assign_str(name); + ), + + TP_printk("%s %s", __get_str(name), show_module_flags(__entry->taints)) +); + +TRACE_EVENT(module_free, + + TP_PROTO(struct module *mod), + + TP_ARGS(mod), + + TP_STRUCT__entry( + __string( name, mod->name ) + ), + + TP_fast_assign( + __assign_str(name); + ), + + TP_printk("%s", __get_str(name)) +); + +#ifdef CONFIG_MODULE_UNLOAD +/* trace_module_get/put are only used if CONFIG_MODULE_UNLOAD is defined */ + +DECLARE_EVENT_CLASS(module_refcnt, + + TP_PROTO(struct module *mod, unsigned long ip), + + TP_ARGS(mod, ip), + + TP_STRUCT__entry( + __field( unsigned long, ip ) + __field( int, refcnt ) + __string( name, mod->name ) + ), + + TP_fast_assign( + __entry->ip = ip; + __entry->refcnt = atomic_read(&mod->refcnt); + __assign_str(name); + ), + + TP_printk("%s call_site=%ps refcnt=%d", + __get_str(name), (void *)__entry->ip, __entry->refcnt) +); + +DEFINE_EVENT(module_refcnt, module_get, + + TP_PROTO(struct module *mod, unsigned long ip), + + TP_ARGS(mod, ip) +); + +DEFINE_EVENT(module_refcnt, module_put, + + TP_PROTO(struct module *mod, unsigned long ip), + + TP_ARGS(mod, ip) +); +#endif /* CONFIG_MODULE_UNLOAD */ + +TRACE_EVENT(module_request, + + TP_PROTO(char *name, bool wait, unsigned long ip), + + TP_ARGS(name, wait, ip), + + TP_STRUCT__entry( + __field( unsigned long, ip ) + __field( bool, wait ) + __string( name, name ) + ), + + TP_fast_assign( + __entry->ip = ip; + __entry->wait = wait; + __assign_str(name); + ), + + TP_printk("%s wait=%d call_site=%ps", + __get_str(name), (int)__entry->wait, (void *)__entry->ip) +); + +#endif /* CONFIG_MODULES */ + +#endif /* _TRACE_MODULE_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1