Hi Jan, I saw the following warning while fuzzing with trinity: [385644.689209] WARNING: CPU: 1 PID: 23536 at mm/truncate.c:740 pagecache_isize_extended+0x124/0x180() [385644.691780] Modules linked in: [385644.692695] CPU: 1 PID: 23536 Comm: trinity-c242 Not tainted 4.2.0-rc5-next-20150806-sasha-00040-g1b47b00-dirty #2417 [385644.695636] ffffffffb21300e0 ffff8800ba3cfc40 ffffffffb1e89dfc 0000000000000000 [385644.708128] ffff8800ba3cfc80 ffffffffa8325106 ffffffffa869fdd4 ffff88006bbe1f10 [385644.710046] 0000000000001007 ffff88006bbe1f60 ffff88006bbe1f10 ffff8803daa965a0 [385644.722774] Call Trace: [385644.723591] dump_stack (lib/dump_stack.c:52) [385644.725180] warn_slowpath_common (kernel/panic.c:448) [385644.728983] warn_slowpath_null (kernel/panic.c:482) [385644.730679] pagecache_isize_extended (mm/truncate.c:740 (discriminator 1)) [385644.732630] truncate_setsize (mm/truncate.c:710) [385644.734469] v9fs_vfs_setattr_dotl (fs/9p/v9fs_vfs.h:81 fs/9p/vfs_inode_dotl.c:593) [385644.753009] notify_change (fs/attr.c:270) [385644.754303] do_truncate (fs/open.c:64) [385644.759181] do_sys_ftruncate.constprop.5 (fs/open.c:193) [385644.760669] SyS_ftruncate (fs/open.c:201) [385644.761818] entry_SYSCALL_64_fastpath (arch/x86/entry/entry_64.S:186) But I'm not really sure how that happens... truncate_setsize() changes the inode size before calling pagecache_isize_extended(): i_size_write(inode, newsize); if (newsize > oldsize) pagecache_isize_extended(inode, oldsize, newsize); truncate_pagecache(inode, newsize); And notify_change() is verifying that i_mutex is held: WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); So it doesn't look like a race either. Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>