The new printk ringbuffer implementation added in kernel v5.10 with
commit 896fbe20b4e2 ("printk: use the lockless ringbuffer") also
exported a new vmcore symbol "clear_seq" to keep track where dmesg had
been cleared like "clear_idx" on previous versions. Use it in
dump_lockless_dmesg when --partial-dmesg is passed to find and start
dumping messages only from that index.Signed-off-by: Ivan Delalande <[email protected]> --- makedumpfile.c | 3 +++ makedumpfile.h | 1 + printk.c | 10 ++++++++++ 3 files changed, 14 insertions(+) diff --git a/makedumpfile.c b/makedumpfile.c index b1b3b42..caf4d12 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -1555,6 +1555,7 @@ get_symbol_info(void) SYMBOL_INIT(pgdat_list, "pgdat_list"); SYMBOL_INIT(contig_page_data, "contig_page_data"); SYMBOL_INIT(prb, "prb"); + SYMBOL_INIT(clear_seq, "clear_seq"); SYMBOL_INIT(log_buf, "log_buf"); SYMBOL_INIT(log_buf_len, "log_buf_len"); SYMBOL_INIT(log_end, "log_end"); @@ -2231,6 +2232,7 @@ write_vmcoreinfo_data(void) WRITE_SYMBOL("pgdat_list", pgdat_list); WRITE_SYMBOL("contig_page_data", contig_page_data); WRITE_SYMBOL("prb", prb); + WRITE_SYMBOL("clear_seq", clear_seq); WRITE_SYMBOL("log_buf", log_buf); WRITE_SYMBOL("log_buf_len", log_buf_len); WRITE_SYMBOL("log_end", log_end); @@ -2676,6 +2678,7 @@ read_vmcoreinfo(void) READ_SYMBOL("pgdat_list", pgdat_list); READ_SYMBOL("contig_page_data", contig_page_data); READ_SYMBOL("prb", prb); + READ_SYMBOL("clear_seq", clear_seq); READ_SYMBOL("log_buf", log_buf); READ_SYMBOL("log_buf_len", log_buf_len); READ_SYMBOL("log_end", log_end); diff --git a/makedumpfile.h b/makedumpfile.h index ca50a89..c57ac7a 100644 --- a/makedumpfile.h +++ b/makedumpfile.h @@ -1656,6 +1656,7 @@ struct symbol_table { unsigned long long pgdat_list; unsigned long long contig_page_data; unsigned long long prb; + unsigned long long clear_seq; unsigned long long log_buf; unsigned long long log_buf_len; unsigned long long log_end; diff --git a/printk.c b/printk.c index e8501c7..a160a5f 100644 --- a/printk.c +++ b/printk.c @@ -145,6 +145,7 @@ dump_record(struct prb_map *m, unsigned long id) int dump_lockless_dmesg(void) { + unsigned long long clear_seq; unsigned long head_id; unsigned long tail_id; unsigned long kaddr; @@ -216,6 +217,15 @@ dump_lockless_dmesg(void) OFFSET(atomic_long_t.counter)); head_id = ULONG(m.desc_ring + OFFSET(prb_desc_ring.head_id) + OFFSET(atomic_long_t.counter)); + if (info->flag_partial_dmesg && SYMBOL(clear_seq) != NOT_FOUND_SYMBOL) { + if (!readmem(VADDR, SYMBOL(clear_seq), &clear_seq, + sizeof(clear_seq))) { + ERRMSG("Can't get clear_seq.\n"); + goto out_text_data; + } + tail_id = head_id - head_id % m.desc_ring_count + + clear_seq % m.desc_ring_count; + } if (!open_dump_file()) { ERRMSG("Can't open output file.\n"); -- 2.32.0 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
