From a64e715fc74b1a7dcc5944f848acc38b2c4d4ee2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 3 Mar 2008 10:12:14 -0800 Subject: Allow ARG_MAX execve string space even with a small stack limit The new code that removed the limitation on the execve string size (which was historically 32 pages) replaced it with a much softer limit based on RLIMIT_STACK which is usually much larger than the traditional limit. See commit b6a2fea39318e43fee84fa7b0b90d68bed92d2ba ("mm: variable length argument support") for details. However, if you have a small stack limit (perhaps because you need lots of stacks in a threaded environment), the new heuristic of allowing up to 1/4th of RLIMIT_STACK to be used for argument and environment strings could actually be smaller than the old limit. So just say that it's ok to have up to ARG_MAX strings regardless of the value of RLIMIT_STACK, and check the rlimit only when going over that traditional limit. (Of course, if you actually have a *really* small stack limit, the whole stack itself will be limited before you hit ARG_MAX, but that has always been true and is clearly the right behaviour anyway). Acked-by: Carlos O'Donell Cc: Michael Kerrisk Cc: Peter Zijlstra Cc: Ollie Wild Signed-off-by: Linus Torvalds --- fs/exec.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/exec.c b/fs/exec.c index a44b142fb46..54a0a557b67 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -173,8 +173,15 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, return NULL; if (write) { - struct rlimit *rlim = current->signal->rlim; unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; + struct rlimit *rlim; + + /* + * We've historically supported up to 32 pages (ARG_MAX) + * of argument strings even with small stacks + */ + if (size <= ARG_MAX) + return page; /* * Limit to 1/4-th the stack size for the argv+env strings. @@ -183,6 +190,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, * - the program will have a reasonable amount of stack left * to work from. */ + rlim = current->signal->rlim; if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { put_page(page); return NULL; -- cgit v1.2.3-70-g09d2 From 78a4a50a86b0a54f7ecbc164267b6c762760254c Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Fri, 29 Feb 2008 22:02:31 -0800 Subject: docbook: fix filesystems.tmpl source files Fix docbook problems in filesystems.tmpl. These cause the generated docbook to be incorrect. Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- fs/buffer.c | 3 +-- fs/jbd/transaction.c | 17 +++++++++-------- fs/mpage.c | 11 +++-------- 3 files changed, 13 insertions(+), 18 deletions(-) (limited to 'fs') diff --git a/fs/buffer.c b/fs/buffer.c index 3ebccf4aa7e..897cd7477b3 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -627,8 +627,7 @@ repeat: } /** - * sync_mapping_buffers - write out and wait upon a mapping's "associated" - * buffers + * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers * @mapping: the mapping which wants those buffers written * * Starts I/O against the buffers at mapping->private_list, and waits upon diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c index 038ed743619..c6cbb6cd59b 100644 --- a/fs/jbd/transaction.c +++ b/fs/jbd/transaction.c @@ -369,7 +369,7 @@ out: /** - * int journal_restart() - restart a handle . + * int journal_restart() - restart a handle. * @handle: handle to restart * @nblocks: nr credits requested * @@ -844,8 +844,7 @@ out: } /** - * int journal_get_undo_access() - Notify intent to modify metadata with - * non-rewindable consequences + * int journal_get_undo_access() - Notify intent to modify metadata with non-rewindable consequences * @handle: transaction * @bh: buffer to undo * @credits: store the number of taken credits here (if not NULL) @@ -921,12 +920,14 @@ out: } /** - * int journal_dirty_data() - mark a buffer as containing dirty data which - * needs to be flushed before we can commit the - * current transaction. + * int journal_dirty_data() - mark a buffer as containing dirty data to be flushed * @handle: transaction * @bh: bufferhead to mark * + * Description: + * Mark a buffer as containing dirty data which needs to be flushed before + * we can commit the current transaction. + * * The buffer is placed on the transaction's data list and is marked as * belonging to the transaction. * @@ -1098,11 +1099,11 @@ no_journal: } /** - * int journal_dirty_metadata() - mark a buffer as containing dirty metadata + * int journal_dirty_metadata() - mark a buffer as containing dirty metadata * @handle: transaction to add buffer to. * @bh: buffer to mark * - * mark dirty metadata which needs to be journaled as part of the current + * Mark dirty metadata which needs to be journaled as part of the current * transaction. * * The buffer is placed on the transaction's metadata list and is marked diff --git a/fs/mpage.c b/fs/mpage.c index 5df564366f3..235e4d3873a 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -325,16 +325,12 @@ confused: } /** - * mpage_readpages - populate an address space with some pages, and - * start reads against them. - * + * mpage_readpages - populate an address space with some pages & start reads against them * @mapping: the address_space * @pages: The address of a list_head which contains the target pages. These * pages have their ->index populated and are otherwise uninitialised. - * * The page at @pages->prev has the lowest file offset, and reads should be * issued in @pages->prev to @pages->next order. - * * @nr_pages: The number of pages at *@pages * @get_block: The filesystem's block mapper function. * @@ -360,6 +356,7 @@ confused: * So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be * submitted in the following order: * 12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 + * * because the indirect block has to be read to get the mappings of blocks * 13,14,15,16. Obviously, this impacts performance. * @@ -656,9 +653,7 @@ out: } /** - * mpage_writepages - walk the list of dirty pages of the given - * address space and writepage() all of them. - * + * mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them * @mapping: address space structure to write * @wbc: subtract the number of written pages from *@wbc->nr_to_write * @get_block: the filesystem's block mapper function. -- cgit v1.2.3-70-g09d2