coredump: only charge written data against RLIMIT_CORE (2c4cb043) · Commits · 戴 / test

Commit ("dump_skip(): dump_seek() replacement taking coredump_params") introduced a regression with regard to RLIMIT_CORE. Previously, when a core dump was sparse, only the data that was actually written out would count against the limit. Now, the sparse ranges are also included, which leads to truncated core dumps when the actual disk usage is still well below the limit. Restore the old behavior by only counting what gets emitted and ignoring what gets skipped. Signed-off-by:

Omar Sandoval <osandov@fb.com> Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/coredump.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -782,7 +782,7 @@ int dump_emit(struct coredump_params cprm, const void addr, int nr)
		struct file *file = cprm->file;
		loff_t pos = file->f_pos;
		ssize_t n;
		if (pos + nr > cprm->limit)
		if (cprm->written + nr > cprm->limit)
		return 0;
		while (nr) {
		if (dump_interrupted())
		@@ -791,6 +791,7 @@ int dump_emit(struct coredump_params cprm, const void addr, int nr)
		if (n <= 0)
		return 0;
		file->f_pos = pos;
		cprm->written += n;
		nr -= n;
		}
		return 1;
		@@ -802,8 +803,6 @@ int dump_skip(struct coredump_params *cprm, size_t nr)
		static char zeroes[PAGE_SIZE];
		struct file *file = cprm->file;
		if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
		if (file->f_pos + nr > cprm->limit)
		return 0;
		if (dump_interrupted() \|\|
		file->f_op->llseek(file, nr, SEEK_CUR) < 0)
		return 0;

include/linux/binfmts.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -64,6 +64,7 @@ struct coredump_params {
		struct file *file;
		unsigned long limit;
		unsigned long mm_flags;
		loff_t written;
		};

		/*

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