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b=EODRVZ78i64iioiiJvZn0gwShjD168VDnpcnxJuxCRm4yrd3zyqZoh5bOljoZiwfe +8zd8Q9os+vLh3jCvABHT2sBtW5p8CFSGyuYO1jtt0rejHv95+7wFzRkbqahwfHilN ZZ04SPifZfBlB28YP6Uv9qzNGZ22HGkkNm8Q2sO0Jn7enprwmJCnAeWCDzguxeEIuA 2d77aG9wT04OX9CE54PYplS27VGLo0FfZ+z4C3KksZsEgrGxw2YsifwwRHuc3oUi83 5Q7pTOpaEN//9knrINWz+Bx1fWSnicpbJvNp88tAK8RXFkTclMq50O5JJWXN7dQMLv 4kbA6gcy4Dbig== From: Christian Brauner Date: Tue, 15 Sep 2026 12:22:16 +0200 Subject: [PATCH 1/6] coredump: don't switch a dumper that has no files table MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260915-work-coredump-fixes-v1-1-f354ca41780c@kernel.org> References: <20260915-work-coredump-fixes-v1-0-f354ca41780c@kernel.org> In-Reply-To: <20260915-work-coredump-fixes-v1-0-f354ca41780c@kernel.org> To: Oleg Nesterov , Jens Axboe , linux-fsdevel@vger.kernel.org Cc: Alexander Viro , Jan Kara , NeilBrown , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, io-uring@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=1162; i=brauner@kernel.org; h=from:subject:message-id; bh=wifUit0zCXT+xmFYL1pQ/rbqJKzU2mv5TqNUZ8hoflY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWStlMmImc9rOo+RqeuSpEnJZ5WmPjunTsOA5JMMBeUe3 xbdzDDpKGVhEONikBVTZHFoNwmXW85TsdkoUwNmDisTyBAGLk4BmMjfZYwM5/eJvpWveKOeNl8w WXaXnm/jmuZnl6TehTm3Ma7X0PzbzsiwXXdnsMA/5dtLX2TtPJVtuDRaOsevkOFpjELZRM6SF15 8AA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 04FFB140008 X-Stat-Signature: yycp8xnndts4r5f34y4bemtp78f7ksb5 X-Rspam-User: X-HE-Tag: 1789467760-577196 X-HE-Meta: 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 dH3GckUD atpng9ImciZNDkL4CzDlCAATPBHcGSPK0TFI941vpkVOrPO4i+8FJyYFjtGz2WfGItqUw68XKbuI0t8RnqLzqA4Z3NgD2nynNrT33mofplqOn7zk78/ellG+sogKvIGSOn2Kneq/l3pVcwn/cO+hLsUzJtPUREbZlGDhJjEJz8ByFbDFm3GMAY53Dl3sD6mHrsiuRhdcSgTobMwBCGP7sKpZpNTxK0kIKGYvOshYeXHpi0YwPQOVNfxm4Qw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Tasks without an fdtable are skipped in coredump_close_files(). The coredump client itself doesn't use the same check. Since put_files_struct() doesn't tolerate NULL it will oops for such tasks without an fdtable. The prime suspect for this behavior are vhost workers. Skip the switch for a coredump client without a table. Fixes: b2b36bcb13ea ("coredump: add COREDUMP_CLOSE_FILES") Signed-off-by: Christian Brauner (Amutable) --- fs/coredump.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/coredump.c b/fs/coredump.c index 1fba3fed1a07..791a9268ed96 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -579,7 +579,11 @@ static bool coredump_close_files(struct core_state *core_state) /* Use the dumper's real creds not the overridden ones. */ scoped_with_creds(current_real_cred()) { io_uring_task_cancel(); - switch_files_struct(current, files); + /* The dumper itself may be a vhost worker without a table. */ + if (current->files) + switch_files_struct(current, files); + else + put_files_struct(files); } coredump_wait_inactive(core_state); -- 2.53.0