56 lines
1.8 KiB
Diff
56 lines
1.8 KiB
Diff
From fa3f0ed47f3e6dbee485722d13713ad495571b7e Mon Sep 17 00:00:00 2001
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From: Lianbo Jiang <lijiang@redhat.com>
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Date: Fri, 23 Aug 2019 20:05:39 +0800
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Subject: [PATCH 4/5] Limit the size of vmcore-dmesg.txt to 2G
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With some corrupted vmcore files, the vmcore-dmesg.txt file may grow
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forever till the kdump disk becomes full, and also probably causes
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the disk error messages as follow:
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...
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sd 0:0:0:0: [sda] tag#6 FAILED Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
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sd 0:0:0:0: [sda] tag#6 CDB: Read(10) 28 00 08 06 4c 98 00 00 08 00
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blk_update_request: I/O error, dev sda, sector 134630552
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sd 0:0:0:0: [sda] tag#7 FAILED Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
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sd 0:0:0:0: [sda] tag#7 CDB: Read(10) 28 00 08 06 4c 98 00 00 08 00
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blk_update_request: I/O error, dev sda, sector 134630552
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...
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If vmcore-dmesg.txt occupies the whole disk, the vmcore can not be
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saved, this is also a problem.
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Lets limit the size of vmcore-dmesg.txt to avoid such problems.
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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Signed-off-by: Simon Horman <horms@verge.net.au>
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---
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vmcore-dmesg/vmcore-dmesg.c | 10 ++++++++++
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1 file changed, 10 insertions(+)
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diff --git a/vmcore-dmesg/vmcore-dmesg.c b/vmcore-dmesg/vmcore-dmesg.c
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index fe7df8ec372c..81c2a58c9d86 100644
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--- a/vmcore-dmesg/vmcore-dmesg.c
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+++ b/vmcore-dmesg/vmcore-dmesg.c
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@@ -5,9 +5,19 @@ typedef Elf32_Nhdr Elf_Nhdr;
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extern const char *fname;
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+/* stole this macro from kernel printk.c */
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+#define LOG_BUF_LEN_MAX (uint32_t)(1 << 31)
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+
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static void write_to_stdout(char *buf, unsigned int nr)
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{
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ssize_t ret;
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+ static uint32_t n_bytes = 0;
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+
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+ n_bytes += nr;
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+ if (n_bytes > LOG_BUF_LEN_MAX) {
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+ fprintf(stderr, "The vmcore-dmesg.txt over 2G in size is not supported.\n");
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+ exit(53);
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+ }
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ret = write(STDOUT_FILENO, buf, nr);
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if (ret != nr) {
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--
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2.17.1
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