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Subject[PATCH] fix double unlock_page() in 2.6.26-rc5-mm3 kernel BUG at mm/filemap.c:575!
This is reproducer of panic. "quick fix" is attached.
But I think putback_lru_page() should be re-designed.

==
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>

int main(int argc, char *argv[])
{
int fd;
char *filename = argv[1];
char buffer[4096];
char *addr;
int len;

fd = open(filename, O_CREAT | O_EXCL | O_RDWR, S_IRWXU);

if (fd < 0) {
perror("open");
exit(1);
}
len = write(fd, buffer, sizeof(buffer));

if (len < 0) {
perror("write");
exit(1);
}

addr = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED|MAP_LOCKED, fd, 0);
if (addr == MAP_FAILED) {
perror("mmap");
exit(1);
}
munmap(addr, 4096);
close(fd);

unlink(filename);
}
==
you'll see panic.

Fix is here
==

quick fix for double unlock_page();

Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com>
Index: linux-2.6.26-rc5-mm3/mm/truncate.c
===================================================================
--- linux-2.6.26-rc5-mm3.orig/mm/truncate.c
+++ linux-2.6.26-rc5-mm3/mm/truncate.c
@@ -104,8 +104,8 @@ truncate_complete_page(struct address_sp

cancel_dirty_page(page, PAGE_CACHE_SIZE);

- remove_from_page_cache(page);
clear_page_mlock(page);
+ remove_from_page_cache(page);
ClearPageUptodate(page);
ClearPageMappedToDisk(page);
page_cache_release(page); /* pagecache ref */


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