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authorClement Calmels <cboulte@gmail.com>2008-08-20 14:09:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-20 15:40:30 -0700
commit1804dc6e145f3f24a8c94deddfc0a986d380a27f (patch)
tree965ad5f3dfa7c6dc52bdfab7d838a82f78c8ad12 /fs
parent35fc908dc0e7ab0002ef18787886cc1340028020 (diff)
/proc/self/maps doesn't display the real file offset
This addresses http://bugzilla.kernel.org/show_bug.cgi?id=11318 In function show_map (file: fs/proc/task_mmu.c), if vma->vm_pgoff > 2^20 than (vma->vm_pgoff << PAGE_SIZE) is greater than 2^32 (with PAGE_SIZE equal to 4096 (i.e. 2^12). The next seq_printf use an unsigned long for the conversion of (vma->vm_pgoff << PAGE_SIZE), as a result the offset value displayed in /proc/self/maps is truncated if the page offset is greater than 2^20. A test that shows this issue: #define _GNU_SOURCE #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <stdlib.h> #include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <string.h> #define PAGE_SIZE (getpagesize()) #if __i386__ # define U64_STR "%llx" #elif __x86_64 # define U64_STR "%lx" #else # error "Architecture Unsupported" #endif int main(int argc, char *argv[]) { int fd; char *addr; off64_t offset = 0x10000000; char *filename = "/dev/zero"; fd = open(filename, O_RDONLY); if (fd < 0) { perror("open"); return 1; } offset *= 0x10; printf("offset = " U64_STR "\n", offset); addr = (char*)mmap64(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, offset); if ((void*)addr == MAP_FAILED) { perror("mmap64"); return 1; } { FILE *fmaps; char *line = NULL; size_t len = 0; ssize_t read; size_t filename_len = strlen(filename); fmaps = fopen("/proc/self/maps", "r"); if (!fmaps) { perror("fopen"); return 1; } while ((read = getline(&line, &len, fmaps)) != -1) { if ((read > filename_len + 1) && (strncmp(&line[read - filename_len - 1], filename, filename_len) == 0)) printf("%s", line); } if (line) free(line); fclose(fmaps); } close(fd); return 0; } [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Clement Calmels <cboulte@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/nommu.c4
-rw-r--r--fs/proc/task_mmu.c4
2 files changed, 4 insertions, 4 deletions
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
index 79ecd281d2cb..3f87d2632947 100644
--- a/fs/proc/nommu.c
+++ b/fs/proc/nommu.c
@@ -52,14 +52,14 @@ int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
}
seq_printf(m,
- "%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
+ "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
vma->vm_start,
vma->vm_end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
- vma->vm_pgoff << PAGE_SHIFT,
+ ((loff_t)vma->vm_pgoff) << PAGE_SHIFT,
MAJOR(dev), MINOR(dev), ino, &len);
if (file) {
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 7546a918f790..73d1891ee625 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -219,14 +219,14 @@ static int show_map(struct seq_file *m, void *v)
ino = inode->i_ino;
}
- seq_printf(m, "%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
+ seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
vma->vm_start,
vma->vm_end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? 's' : 'p',
- vma->vm_pgoff << PAGE_SHIFT,
+ ((loff_t)vma->vm_pgoff) << PAGE_SHIFT,
MAJOR(dev), MINOR(dev), ino, &len);
/*

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