From 7e57523490cd2efb52b1ea97f2e0a74c0fb634cd Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 18 Mar 2026 15:38:58 +0000 Subject: [PATCH] netfs: Fix read abandonment during retry Under certain circumstances, all the remaining subrequests from a read request will get abandoned during retry. The abandonment process expects the 'subreq' variable to be set to the place to start abandonment from, but it doesn't always have a useful value (it will be uninitialised on the first pass through the loop and it may point to a deleted subrequest on later passes). Fix the first jump to "abandon:" to set subreq to the start of the first subrequest expected to need retry (which, in this abandonment case, turned out unexpectedly to no longer have NEED_RETRY set). Also clear the subreq pointer after discarding superfluous retryable subrequests to cause an oops if we do try to access it. Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Signed-off-by: David Howells Link: https://patch.msgid.link/3775287.1773848338@warthog.procyon.org.uk Reviewed-by: Paulo Alcantara (Red Hat) cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/read_retry.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c index 7793ba5e3e8f..cca9ac43c077 100644 --- a/fs/netfs/read_retry.c +++ b/fs/netfs/read_retry.c @@ -93,8 +93,10 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) from->start, from->transferred, from->len); if (test_bit(NETFS_SREQ_FAILED, &from->flags) || - !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags)) + !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags)) { + subreq = from; goto abandon; + } list_for_each_continue(next, &stream->subrequests) { subreq = list_entry(next, struct netfs_io_subrequest, rreq_link); @@ -178,6 +180,7 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) if (subreq == to) break; } + subreq = NULL; continue; }