Although ring_buffer_per_cpu::nr_pages is defined as unsigned long, it is capped to 32-bits in a few places, limiting the operations possible on a very large buffer. Use `unsigned long` where appropriate and prevent truncation of values using nr_pages (or nr_subbufs).
While at it, subbuf_size must be at least `unsigned int`. Note that persistent, remote and user-mapped ring buffers are capping the number of pages to 31 bits already, making "int" safe in many places. Signed-off-by: Vincent Donnefort <[email protected]> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5e26eeff588f..7d22f10df3d6 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1678,7 +1678,7 @@ static void rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer) * This is used to help find the next per cpu subbuffer within a mapped range. */ static unsigned long -rb_range_align_subbuf(unsigned long addr, int subbuf_size, int nr_subbufs) +rb_range_align_subbuf(unsigned long addr, unsigned int subbuf_size, unsigned long nr_subbufs) { addr += sizeof(struct ring_buffer_cpu_meta) + sizeof(int) * nr_subbufs; @@ -1688,13 +1688,12 @@ rb_range_align_subbuf(unsigned long addr, int subbuf_size, int nr_subbufs) /* * Return the ring_buffer_meta for a given @cpu. */ -static void *rb_range_meta(struct trace_buffer *buffer, int nr_pages, int cpu) +static void *rb_range_meta(struct trace_buffer *buffer, unsigned long nr_pages, int cpu) { - int subbuf_size = rb_subbuf_size(buffer); + unsigned int subbuf_size = rb_subbuf_size(buffer); struct ring_buffer_cpu_meta *meta; struct ring_buffer_meta *bmeta; - unsigned long ptr; - int nr_subbufs; + unsigned long ptr, nr_subbufs; bmeta = buffer->meta; if (!bmeta) @@ -1740,7 +1739,7 @@ static void *rb_range_meta(struct trace_buffer *buffer, int nr_pages, int cpu) /* Return the start of subbufs given the meta pointer */ static void *rb_subbufs_from_meta(struct ring_buffer_cpu_meta *meta) { - int subbuf_size = meta->subbuf_size; + unsigned int subbuf_size = meta->subbuf_size; unsigned long ptr; ptr = (unsigned long)meta; @@ -1752,11 +1751,11 @@ static void *rb_subbufs_from_meta(struct ring_buffer_cpu_meta *meta) /* * Return a specific sub-buffer for a given @cpu defined by @idx. */ -static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int idx) +static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, unsigned int idx) { struct ring_buffer_cpu_meta *meta; + unsigned int subbuf_size; unsigned long ptr; - int subbuf_size; meta = rb_range_meta(cpu_buffer->buffer, 0, cpu_buffer->cpu); if (!meta) @@ -1772,7 +1771,7 @@ static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int idx) ptr = (unsigned long)rb_subbufs_from_meta(meta); - ptr += subbuf_size * idx; + ptr += (unsigned long)subbuf_size * idx; if (ptr + subbuf_size > cpu_buffer->buffer->range_addr_end) return NULL; @@ -1849,13 +1848,13 @@ static bool rb_meta_init(struct trace_buffer *buffer, int scratch_size) * must be the same. */ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu, - struct trace_buffer *buffer, int nr_pages, + struct trace_buffer *buffer, unsigned long nr_pages, unsigned long *subbuf_mask) { - int subbuf_size = PAGE_SIZE; + unsigned long subbuf_size = PAGE_SIZE; unsigned long buffers_start; unsigned long buffers_end; - int i; + unsigned long i; if (!subbuf_mask) return false; @@ -2104,8 +2103,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) struct buffer_page *head_page, *orig_head, *orig_reader; struct rb_validation_state state = { 0 }; bool skip = false; + unsigned long i; int ret; - int i; if (!meta || !meta->head_buffer) return; @@ -2156,7 +2155,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) rb_validate_buffer(head_page, cpu_buffer, meta, &state, 0, state.ts); } if (i) - pr_info("Ring buffer [%d] rewound %d pages\n", cpu_buffer->cpu, i); + pr_info("Ring buffer [%d] rewound %lu pages\n", cpu_buffer->cpu, i); /* The last rewound page must be skipped. */ if (head_page != orig_head) @@ -2240,7 +2239,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) } } -static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages, int scratch_size) +static void rb_range_meta_init(struct trace_buffer *buffer, + unsigned long nr_pages, int scratch_size) { struct ring_buffer_cpu_meta *meta; unsigned long *subbuf_mask; @@ -2340,8 +2340,8 @@ static int rbm_show(struct seq_file *m, void *v) rb_meta_subbuf_idx(meta, (void *)meta->head_buffer)); seq_printf(m, "commit_buffer: %d\n", rb_meta_subbuf_idx(meta, (void *)meta->commit_buffer)); - seq_printf(m, "subbuf_size: %d\n", meta->subbuf_size); - seq_printf(m, "nr_subbufs: %d\n", meta->nr_subbufs); + seq_printf(m, "subbuf_size: %u\n", meta->subbuf_size); + seq_printf(m, "nr_subbufs: %u\n", meta->nr_subbufs); return 0; } @@ -2426,7 +2426,7 @@ static void *ring_buffer_desc_page(struct ring_buffer_desc *desc, unsigned int p } static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, - long nr_pages, struct list_head *pages) + unsigned long nr_pages, struct list_head *pages) { struct trace_buffer *buffer = cpu_buffer->buffer; struct ring_buffer_cpu_meta *meta = NULL; @@ -2554,7 +2554,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, } static struct ring_buffer_per_cpu * -rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) +rb_allocate_cpu_buffer(struct trace_buffer *buffer, unsigned long nr_pages, int cpu) { struct ring_buffer_per_cpu *cpu_buffer __free(kfree) = alloc_cpu_buffer(cpu); @@ -2711,8 +2711,8 @@ static void rb_test_inject_invalid_pages(struct trace_buffer *buffer) struct ring_buffer_cpu_meta *meta; struct buffer_data_page *dpage; unsigned long entry_bytes = 0; + unsigned int subbuf_size; unsigned long ptr; - int subbuf_size; int invalid = 0; int cpu; int i; @@ -2782,8 +2782,8 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, struct ring_buffer_remote *remote) { struct trace_buffer *buffer __free(kfree) = NULL; - long nr_pages; - int subbuf_size; + unsigned int subbuf_size; + unsigned long nr_pages; int bsize; int cpu; int ret; @@ -5867,12 +5867,12 @@ __rb_get_reader_page_from_remote(struct ring_buffer_per_cpu *cpu_buffer) static struct buffer_page * __rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) { - int max_loops = cpu_buffer->ring_meta ? cpu_buffer->nr_pages : 3; + unsigned long max_loops = cpu_buffer->ring_meta ? cpu_buffer->nr_pages : 3; struct buffer_page *reader = NULL; + unsigned long nr_loops = 0; unsigned long overwrite; unsigned long flags; int missed_events = 0; - int nr_loops = 0; bool ret; local_irq_save(flags); @@ -6190,8 +6190,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct trace_buffer *buffer; struct ring_buffer_per_cpu *cpu_buffer; struct ring_buffer_event *event; - int nr_loops = 0; - int max_loops; + unsigned long nr_loops = 0; + unsigned long max_loops; if (ts) *ts = 0; @@ -7438,8 +7438,8 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) struct ring_buffer_per_cpu *cpu_buffer; struct buffer_page *bpage, *tmp; unsigned int old_capacity; + unsigned long nr_pages; int old_order; - int nr_pages; int psize; int err; int cpu; @@ -7621,10 +7621,10 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, struct buffer_page **subbuf_ids) { struct trace_buffer_meta *meta = cpu_buffer->meta_page; - unsigned int nr_subbufs = cpu_buffer->nr_pages + 1; + unsigned long nr_subbufs = cpu_buffer->nr_pages + 1; struct buffer_page *first_subbuf, *subbuf; - int cnt = 0; - int id = 0; + unsigned int cnt = 0; + unsigned int id = 0; id = rb_page_id(cpu_buffer, cpu_buffer->reader_page, id); subbuf_ids[id++] = cpu_buffer->reader_page; -- 2.55.0.691.gc56d675ccc-goog
