Re: [uml-devel] fuzz tested 32 bit user mode linux image hangs inradix_tree_next_chunk()
From: Toralf FÃrster
Date: Fri Nov 22 2013 - 15:35:49 EST
On 11/06/2013 10:31 PM, Richard Weinberger wrote:
> Can you please ask gdb for the value of offset?
With this diff against latest Linus tree v3.12-11355-g57498f9 :
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 7811ed3..54d9802 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -750,6 +750,7 @@ restart:
/* Index outside of the tree */
if (offset >= RADIX_TREE_MAP_SIZE)
return NULL;
+ printk ("offset a: %lu \n", offset);
node = rnode;
while (1) {
@@ -770,6 +771,7 @@ restart:
if (node->slots[offset])
break;
}
+ printk ("offset b: %lu \n", offset);
index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1);
index += offset << shift;
/* Overflow after ~0UL */
@@ -812,6 +814,7 @@ restart:
}
}
+ printk ("offset c: %lu \n", offset);
return node->slots + offset;
}
EXPORT_SYMBOL(radix_tree_next_chunk);
I got today these syslog message when the trinity process hangs at a 32 bit Gentoo linux:
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset c: 63
Nov 22 21:29:29 trinity kernel: offset a: 0
Nov 22 21:29:29 trinity kernel: offset b: 3
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset c: 63
Nov 22 21:29:29 trinity kernel: offset a: 0
Nov 22 21:29:29 trinity kernel: offset b: 3
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity sshd[1299]: pam_unix(sshd:session): session closed for user tfoerste
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset c: 63
Nov 22 21:29:29 trinity kernel: offset a: 0
Nov 22 21:29:29 trinity kernel: offset b: 3
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:29 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset c: 63
Nov 22 21:29:30 trinity kernel: offset a: 0
Nov 22 21:29:30 trinity kernel: offset b: 3
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset c: 63
Nov 22 21:29:30 trinity kernel: offset a: 0
Nov 22 21:29:30 trinity kernel: offset b: 3
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity sshd[1533]: pam_unix(sshd:session): session opened for user root by (uid=0)
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset b: 63
Nov 22 21:29:30 trinity kernel: offset c: 63
Nov 22 21:29:30 trinity kernel: offset a: 0
Nov 22 21:29:30 trinity kernel: offset b: 3
Nov 22 21:29:31 trinity kernel: offset b: 63
Nov 22 21:29:31 trinity kernel: offset b: 63
Nov 22 21:29:31 trinity kernel: offset b: 63
Nov 22 21:29:31 trinity kernel: offset b: 63
Nov 22 21:29:31 trinity kernel: offset b: 63
Nov 22 21:29:31 trinity kernel: offset c: 63
Nov 22 21:29:31 trinity shutdown[1536]: shutting down for system halt
Nov 22 21:29:31 trinity init: Switching to runlevel: 0
FWIW gdb's output :
tfoerste@n22 ~/devel/linux $ sudo gdb /home/tfoerste/devel/linux/linux 3612 -n -batch -ex bt
0x083d3c83 in memcpy ()
#0 0x083d3c83 in memcpy ()
#1 0x080a6257 in log_store (facility=0, level=4, flags=LOG_NEWLINE, ts_nsec=0, dict=0x86101e0 <__log_buf+25512> "\200=\355\265D", dict_len=0, text=0x86101e0 <__log_buf+25512> "\200=\355\265D", text_len=13) at kernel/printk/printk.c:344
#2 0x080a7158 in vprintk_emit (facility=0, level=4, dict=0x0, dictlen=0, fmt=0x63a8 <Address 0x63a8 out of bounds>, args=0x63a8 <Address 0x63a8 out of bounds>) at kernel/printk/printk.c:1610
#3 0x08423845 in printk (fmt=0x63a8 <Address 0x63a8 out of bounds>) at kernel/printk/printk.c:1690
#4 0x0829c39e in radix_tree_next_chunk (root=0x63a8, iter=0x3f, flags=0) at lib/radix-tree.c:774
#5 0x080cc78e in find_get_pages (mapping=0x48c21010, start=0, nr_pages=14, pages=0x86101e0 <__log_buf+25512>) at mm/filemap.c:844
#6 0x080d654a in pagevec_lookup (pvec=0x49bffcc8, mapping=0x63a8, start=25512, nr_pages=25512) at mm/swap.c:937
#7 0x080d694a in truncate_inode_pages_range (mapping=0x48c21010, lstart=0, lend=-1) at mm/truncate.c:241
#8 0x080d6cef in truncate_inode_pages (mapping=0x63a8, lstart=603765886628684712) at mm/truncate.c:358
#9 0x08260a48 in hostfs_evict_inode (inode=0x48c20f58) at fs/hostfs/hostfs_kern.c:233
#10 0x0811b46f in evict (inode=0x48c20f58) at fs/inode.c:549
#11 0x0811bf5d in iput_final (inode=<optimized out>) at fs/inode.c:1419
#12 iput (inode=0x48c20f58) at fs/inode.c:1437
#13 0x08118858 in dentry_iput (dentry=<optimized out>) at fs/dcache.c:300
#14 d_kill (parent=<optimized out>, dentry=<optimized out>) at fs/dcache.c:447
#15 dentry_kill (dentry=0x4957de70, unlock_on_failure=<optimized out>) at fs/dcache.c:549
#16 0x08118b5d in dput (dentry=0x4957de70) at fs/dcache.c:605
#17 0x08105353 in __fput (file=0x48a7cd80) at fs/file_table.c:261
#18 0x081053bb in ____fput (work=0x48a7cd80) at fs/file_table.c:279
#19 0x08094486 in task_work_run () at kernel/task_work.c:123
#20 0x0807efb2 in exit_task_work (task=<optimized out>) at include/linux/task_work.h:21
#21 do_exit (code=1217397248) at kernel/exit.c:787
#22 0x0807f5fd in do_group_exit (exit_code=0) at kernel/exit.c:920
#23 0x0807f669 in SYSC_exit_group (error_code=<optimized out>) at kernel/exit.c:931
#24 SyS_exit_group (error_code=0) at kernel/exit.c:929
#25 0x08062ab4 in handle_syscall (r=0x48a787cc) at arch/um/kernel/skas/syscall.c:35
#26 0x08075115 in handle_trap (local_using_sysemu=<optimized out>, regs=<optimized out>, pid=<optimized out>) at arch/um/os-Linux/skas/process.c:198
#27 userspace (regs=0x48a787cc) at arch/um/os-Linux/skas/process.c:431
#28 0x0805f770 in fork_handler () at arch/um/kernel/process.c:149
#29 0x00000000 in ?? ()
--
MfG/Sincerely
Toralf FÃrster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
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