c.RWLayer: check for nil before use - #36242
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cpuguy83
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We should probably check if the container is in the dead state first.
This would allow us to give a better error message.
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Just here or in mount/unmount as well?
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+1 for checking for container.Dead here, unmount and in Windows, like in ContainerChanges
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Please see the updated version
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Well, adding a check for container.Dead is a change in workflow -- meaning we no longer mount/unmount containers in Dead state. I'm not quite sure if this is the right change....
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reverted the check for container.Dead in mount/umount/change, leaving only in getInspectData where a similar check was before

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LGTM |
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There seems to be a deadlock in inspect. |
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Since commit e9b9e4a has landed, there is a chance that container.RWLayer is nil (due to some half-removed container). Let's check the pointer before use to avoid any potential nil pointer dereferences, resulting in a daemon crash. Note that even without the abovementioned commit, it's better to perform an extra check (even it's totally redundant) rather than to have a possibility of a daemon crash. In other words, better be safe than sorry. [v2: add a test case for daemon.getInspectData] [v3: add a check for container.Dead and a special error for the case] Fixes: e9b9e4a Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
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Previously the RWLayer reference was cleared without holding the mutex. This could lead to goroutine panics in various places that use the container.RWLayer because nil checks introduced in moby#36242 where not sufficient as the reference could change after the check for nil and before the reference use. Signed-off-by: Tadeusz Dudkiewicz <tadeusz.dudkiewicz@rtbhouse.com>
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Previously the RWLayer reference was cleared without holding the container lock. This could lead to goroutine panics in various places that use the container.RWLayer because nil checks introduced in moby#36242 where not sufficient as the reference could change right before the use. Fixes moby#49227 Signed-off-by: Tadeusz Dudkiewicz <tadeusz.dudkiewicz@rtbhouse.com>
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Previously the RWLayer reference was cleared without holding the container lock. This could lead to goroutine panics in various places that use the container.RWLayer because nil checks introduced in moby#36242 where not sufficient as the reference could change right before the use. Fixes moby#49227 Signed-off-by: Tadeusz Dudkiewicz <tadeusz.dudkiewicz@rtbhouse.com> (cherry picked from commit 97dc305) Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
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Since commit e9b9e4a (#36160) has landed, there is a chance that
container.RWLayer is nil (due to some half-removed container). Let's
check the pointer before use to avoid any potential nil pointer
dereferences, resulting in a daemon crash.
Note that even without the abovementioned commit, it's better to perform
an extra check (even it's totally redundant) rather than to have a
possibility of a daemon crash. In other words, better be safe than
sorry.
Fixes: e9b9e4a
Signed-off-by: Kir Kolyshkin kolyshkin@gmail.com
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