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From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Jeremy Kerr <jk@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
	Oleg Nesterov <oleg@redhat.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	x86@kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 7/7] binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump
Date: Tue,  5 May 2020 12:12:56 +0200	[thread overview]
Message-ID: <20200505101256.3121270-8-hch@lst.de> (raw)
In-Reply-To: <20200505101256.3121270-1-hch@lst.de>

There is no logic in elf_fdpic_core_dump itself or in the various arch
helpers called from it which use uaccess routines on kernel pointers
except for the file writes thate are nicely encapsulated by using
__kernel_write in dump_emit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/binfmt_elf_fdpic.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 240f666635437..d9501a86cec97 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1549,7 +1549,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 {
 #define	NUM_NOTES	6
 	int has_dumped = 0;
-	mm_segment_t fs;
 	int segs;
 	int i;
 	struct vm_area_struct *vma;
@@ -1589,31 +1588,31 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	/* alloc memory for large data structures: too large to be on stack */
 	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
 	if (!elf)
-		goto cleanup;
+		goto end_coredump;
 	prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
 	if (!prstatus)
-		goto cleanup;
+		goto end_coredump;
 	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
 	if (!psinfo)
-		goto cleanup;
+		goto end_coredump;
 	notes = kmalloc_array(NUM_NOTES, sizeof(struct memelfnote),
 			      GFP_KERNEL);
 	if (!notes)
-		goto cleanup;
+		goto end_coredump;
 	fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
 	if (!fpu)
-		goto cleanup;
+		goto end_coredump;
 #ifdef ELF_CORE_COPY_XFPREGS
 	xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
 	if (!xfpu)
-		goto cleanup;
+		goto end_coredump;
 #endif
 
 	for (ct = current->mm->core_state->dumper.next;
 					ct; ct = ct->next) {
 		tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
 		if (!tmp)
-			goto cleanup;
+			goto end_coredump;
 
 		tmp->thread = ct->task;
 		list_add(&tmp->list, &thread_list);
@@ -1678,9 +1677,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 			  "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
 #endif
 
-	fs = get_fs();
-	set_fs(KERNEL_DS);
-
 	offset += sizeof(*elf);				/* Elf header */
 	offset += segs * sizeof(struct elf_phdr);	/* Program headers */
 
@@ -1788,9 +1784,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	}
 
 end_coredump:
-	set_fs(fs);
-
-cleanup:
 	while (!list_empty(&thread_list)) {
 		struct list_head *tmp = thread_list.next;
 		list_del(tmp);
-- 
2.26.2


  parent reply	other threads:[~2020-05-05 10:13 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 10:12 remove set_fs calls from the coredump code v6 Christoph Hellwig
2020-05-05 10:12 ` [PATCH 1/7] powerpc/spufs: fix copy_to_user while atomic Christoph Hellwig
2020-05-05 10:12 ` [PATCH 2/7] powerpc/spufs: stop using access_ok Christoph Hellwig
2020-05-05 10:12 ` [PATCH 3/7] powerpc/spufs: simplify spufs core dumping Christoph Hellwig
2020-05-05 10:12 ` [PATCH 4/7] signal: refactor copy_siginfo_to_user32 Christoph Hellwig
2020-05-05 10:12 ` [PATCH 5/7] binfmt_elf: remove the set_fs in fill_siginfo_note Christoph Hellwig
2020-05-05 10:12 ` [PATCH 6/7] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Christoph Hellwig
2020-05-05 10:12 ` Christoph Hellwig [this message]
2020-05-05 16:52 ` remove set_fs calls from the coredump code v6 Linus Torvalds
2020-05-05 20:28   ` Eric W. Biederman
2020-05-06  6:31     ` Christoph Hellwig
2020-05-06 15:44       ` Eric W. Biederman
2020-05-05 20:34 ` Al Viro
2020-05-05 20:42   ` Christoph Hellwig
2020-05-05 20:47     ` Al Viro

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